A048176: Triangle read by rows: T(n, m) = S1(n, m)*10^(n-m), where S1 are the signed Stirling numbers of first kind A008275 (n >= 1, 1 <= m <= n).

A028338 → x ↦ (−1/5)x+1

A048176 only rational roots

Proved for all n: all roots real, in [5, ∞) · alternating coefficient signs · interlacing (weak) what this means

Recurrence from OEIS A048176
\(P_{n}(x) = \left(x - 10\,n\right)\,P_{n-1}(x)\)
\(P_{0}(x) = 1\)

Rows ?

nx0x1x2x3x4x5x6x7x8x9x10x11x12x13x14Pn(1)
011
1-101-9
2200-301171
3-60001100-601-4959
4240000-500003500-1001193401
5-120000002740000-2250008500-1501-9476649
6720000000-17640000016240000-73500017500-2101559122291
7-5040000000013068000000-131320000067690000-196000032200-2801-38579438079
84032000000000-1095840000000118124000000-6728400000224490000-453600054600-36013047775608241
9-362880000000000102657600000000-11727000000000723680000000-26932500000632730000-945000087000-4501-271252029133449
1036288000000000000-106286400000000001275357600000000-840950000000003416930000000-902055000001577730000-18150000132000-550126853950884211451
11-39916800000000000001205438400000000000-15091797600000000010525807600000000-45995730000000013339535000000-2637558000003574230000-32670000192500-6601-2927080646379048159
12479001600000000000000-14864428800000000000019315595520000000000-141401488800000000065720683600000000-206070150000000044990231000000-6926634000007494630000-55770000271700-7801348322596919106730921
13-6227020800000000000000019802759040000000000000-2659671705600000000000203137530960000000000-9957703756000000000333611878600000000-7909431530000000135036473000000-166696530000014744730000-91091000373100-9101-44933615002564768288809
148717829120000000000000000-2834656473600000000000000392156797824000000000000-310989260400000000000001597216056800000000000-566633667600000000001440932292800000000-26814537750000000368411615000000-373122750000027497470000-143325000500500-105016245772485356502792144451

Generated b-files: A048176 ?

Computed in your browser ?

Technical details
Node id
n-f45d29a8d57e6cc8 · revision 1 · JSON
Definition source
oeis_catalog:A048176
Fingerprint
f6-0f5f9e74c0cf88d5

Observed on the stored rows ?

  • Degrees: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 (affine: slope 1, intercept 0)
  • Palindromic rows: no
  • γ-positive (gamma_positive): no
  • Nonnegative coefficients (nonn): no
  • Only rational roots (rr_by_factors: every nonzero row is a product of linear factors over ℚ): yes

OEIS matches ?

A generated b-file is computed from the node's definition along the row alignment of its OEIS link and starts at the entry's offset. It is an identification on a finite prefix, not a proof that the node and the OEIS entry agree for every n.

OEIS submission text ?

Fields to paste into an OEIS submission: the example %e, the formula %F and programs %t (Mathematica) and %o (PARI/GP) that list the same rows. For an OEIS link the row numbers, the offset and the orientation are those of the entry, as matched; the matched terms were compared with the published ones, which identifies the node with the entry on a finite prefix, not for every n. The PARI/GP program is not machine-checked here.

The atlas's own rows: n = 0, …, ascending powers of x
%e Example
Triangle begins:
  0:                1;
  1:              -10,               1;
  2:              200,             -30,               1;
  3:            -6000,            1100,             -60,            1;
  4:           240000,          -50000,            3500,         -100,            1;
  5:        -12000000,         2740000,         -225000,         8500,         -150,         1;
  6:        720000000,      -176400000,        16240000,      -735000,        17500,      -210,        1;
  7:     -50400000000,     13068000000,     -1313200000,     67690000,     -1960000,     32200,     -280,     1;
  8:    4032000000000,  -1095840000000,    118124000000,  -6728400000,    224490000,  -4536000,    54600,  -360,    1;
  9: -362880000000000, 102657600000000, -11727000000000, 723680000000, -26932500000, 632730000, -9450000, 87000, -450, 1;
%F Formula
The row polynomials satisfy P(n,x) = -(10*n-x)*P(n-1,x) for n >= 1, with P(0,x) = 1.
%t Mathematica
P[0, x_] := 1;
P[n_, x_] := P[n, x] = Expand[-(10*n - x)*P[n - 1, x]];
Table[CoefficientList[P[n, x], x], {n, 0, 9}] // Flatten
%o PARI/GP
P(N) = {my(v = vector(N + 1)); v[1] = 1; for(n = 1, N, my(i = n + 1); v[i] = -(10*n - x)*v[i - 1]); v};
row(n, p) = {my(c = Vecrev(p)); c};
T(N) = {my(v = P(N)); concat(vector(#v, i, row(i - 1, v[i])))};
T(9)

Generated with polytool c48629374597.

A048176: triangle, offset 1, from the row P0
%e Example
Triangle begins:
   1:                1;
   2:              -10,               1;
   3:              200,             -30,               1;
   4:            -6000,            1100,             -60,            1;
   5:           240000,          -50000,            3500,         -100,            1;
   6:        -12000000,         2740000,         -225000,         8500,         -150,         1;
   7:        720000000,      -176400000,        16240000,      -735000,        17500,      -210,        1;
   8:     -50400000000,     13068000000,     -1313200000,     67690000,     -1960000,     32200,     -280,     1;
   9:    4032000000000,  -1095840000000,    118124000000,  -6728400000,    224490000,  -4536000,    54600,  -360,    1;
  10: -362880000000000, 102657600000000, -11727000000000, 723680000000, -26932500000, 632730000, -9450000, 87000, -450, 1;
%F Formula
The row polynomials satisfy P(n,x) = -(10*n-10-x)*P(n-1,x) for n >= 2, with P(1,x) = 1.
%t Mathematica
P[1, x_] := 1;
P[n_, x_] := P[n, x] = Expand[-(10*n - 10 - x)*P[n - 1, x]];
Table[PadRight[CoefficientList[P[n, x], x], n], {n, 1, 10}] // Flatten
%o PARI/GP
P(N) = {my(v = vector(N)); v[1] = 1; for(n = 2, N, my(i = n); v[i] = -(10*n - 10 - x)*v[i - 1]); v};
row(n, p) = {my(c = Vecrev(p)); c = concat(c, vector(n - #c)); c};
T(N) = {my(v = P(N)); concat(vector(#v, i, row(i, v[i])))};
T(10)

Generated with polytool c48629374597.

Proved properties

  • Real-rooted. Every row P_n, n >= 0, is zero or real-rooted with all roots in [5, +inf)
    Every polynomial of the sequence has only real roots, inside the stated interval.
    by the cited steps: e-040c826eba4e7d74
  • Coefficients of one sign. Every nonzero row, n >= 0: the coefficients of P_n(-x) have one sign
    All coefficients of each polynomial have the same sign (after x -> -x when alternating).
    derived from the cited steps by a stated theorem: e-040c826eba4e7d74
  • Interlacing of consecutive rows. Rows P_(m-1), P_m interlace (weak, unordered) for every m >= 1
    The roots of consecutive polynomials alternate on the real line.
    by the cited steps: e-040c826eba4e7d74

Proof chains

1 incoming proof step. Each step is expanded back to the roots of the proof DAG, the theorem checks of a node's own rule. JSON

Used in 2 proof steps

No candidate equalities or related sequences.

References

  1. [LW07] Lily L. Liu and Yi Wang. A unified approach to polynomial sequences with only real zeros. Advances in Applied Mathematics, 38(4):542–560, May 2007. doi:10.1016/j.aam.2006.02.003