basis-map coefficients of A112227 → (θ+1)² → basis A013609

nonnegative coefficientsonly rational roots

Proved for all n all roots real, in (−∞, 0]coefficients of one signHadamard kernelinterlacing (weak)

Recurrence

\(\left(1 + 2\,n + n^{2}\right)\,P_{n}(x) = \left(4 + 8\,x + 4\,n + 8\,n x + n^{2} + 2\,n^{2} x\right)\,P_{n-1}(x)\)
\(P_{1}(x) = 9 + 36\,x + 36\,x^{2}\)

Rows ?

nx0x1x2x3x4x5x6x7x8x9x10x11x12x13x14x15x16Pn(1)
19363681
21696192128432
3252006008004002025
43636014402880288011528748
54958829407840117609408313635721
6648965376179203584043008286728192139968
7811296907236288907201451521451528294420736531441
810018001440067200201600403200537600460800230400512001968300
91212420217801161604065609757441626240185856013939206195201239047144929
1014431683168019008076032021288964257792608256060825604055040162201629491225509168
1116940564461629744013384804283136999398417132544214156801903616011421696415334469222489813529
1219650966115244844822422408072064215255044305100864576512717516805740134431309824104366081605632312487308
132256300819006552003603600144144004324320098841600172972800230630400230630400167731200838656002580480036864001076168025
142567680107520931840559104024600576820019202108620804217241606560153607872184327156531204771020802202009606291456083886083673320192
1528992481387201294720841568040395264148115968423188480952174080169275392023698554882585296896215441408013257932805681971201515192321893990412440502369
Technical details
Node id
n-447d7ea348d137e5 · revision 0 · JSON
Definition source
derived:basis_map_A013609
Fingerprint
f6-11aec07ce60b6d61

Observed on the stored rows ?

  • Degrees: 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 (affine: slope 1, intercept 1)
  • Palindromic rows: no
  • γ-positive (gamma_positive): no
  • Nonnegative coefficients (nonn): yes
  • Only rational roots (rr_by_factors: every nonzero row is a product of linear factors over ℚ): yes

Matches ?

No OEIS matches.

Submission text ?

Atlas rows n = 1, …, ascending powers of x
%e Example
Triangle begins:
   1:   9,   36,    36;
   2:  16,   96,   192,    128;
   3:  25,  200,   600,    800,    400;
   4:  36,  360,  1440,   2880,   2880,    1152;
   5:  49,  588,  2940,   7840,  11760,    9408,    3136;
   6:  64,  896,  5376,  17920,  35840,   43008,   28672,    8192;
   7:  81, 1296,  9072,  36288,  90720,  145152,  145152,   82944,   20736;
   8: 100, 1800, 14400,  67200, 201600,  403200,  537600,  460800,  230400,   51200;
   9: 121, 2420, 21780, 116160, 406560,  975744, 1626240, 1858560, 1393920,  619520,  123904;
  10: 144, 3168, 31680, 190080, 760320, 2128896, 4257792, 6082560, 6082560, 4055040, 1622016, 294912;
%F Formula
The row polynomials satisfy (n^2+2*n+1)*P(n,x) = (n^2+4*n+4+(2*n^2+8*n+8)*x)*P(n-1,x) for n >= 2, with P(1,x) = 9 + 36*x + 36*x^2.
%t Mathematica
P[1, x_] := 9 + 36*x + 36*x^2;
P[n_, x_] := P[n, x] = Expand[Together[((n^2 + 4*n + 4 + (2*n^2 + 8*n + 8)*x)*P[n - 1, x])/(n^2 + 2*n + 1)]];
Table[CoefficientList[P[n, x], x], {n, 1, 10}] // Flatten
%o PARI/GP
P(N) = {my(v = vector(N)); v[1] = 9 + 36*x + 36*x^2; for(n = 2, N, my(i = n); v[i] = ((n^2 + 4*n + 4 + (2*n^2 + 8*n + 8)*x)*v[i - 1])/(n^2 + 2*n + 1)); v};
row(n, p) = {my(c = Vecrev(p)); c};
T(N) = {my(v = P(N)); concat(vector(#v, i, row(i, v[i])))};
T(10)

polytool c48629374597

Properties

Proof chains ? JSON

Same fingerprint ?

References

  1. [Bra06] Petter Brändén. On linear transformations preserving the Pólya frequency property. Transactions of the American Mathematical Society, 358(8):3697–3716, February 2006. doi:10.1090/s0002-9947-06-03856-6
  2. [Bra15] Petter Brändén. Unimodality, log-concavity, real-rootedness and beyond. Handbook of enumerative combinatorics, :437–483, March 2015. doi:10.1201/b18255-10
  3. [SP14] J Schur and G Polya. Über zwei Arten von Faktorenfolgen in der Theorie der algebraischen Gleichungen. J. Reine Angew. Math., 1914.