A003506

View A003506 at the OEIS

identification: the entry's rule defines the sequence for every index; tail: the sequence is the entry's tail after some prefix rows; match_*: finite agreement only.

• A003506: Triangle of denominators in Leibniz's Harmonic Triangle a(n,k), n >= 1, 1 <= k <= n. (identification, match reversed triangle, match triangle)
  A007318 → D
  1 · 2, 2 · 3, 6, 3 · 4, 12, 12, 4 … row sums 1, 4, 12, 32, 80, 192, 448, 1024, …
  A003506 (−∞, 0] nonnegative rational roots
• A216973: Exponential Riordan array [x*exp(x),x]. (match reversed triangle, match triangle)
  A007318 → D
  1 · 2, 2 · 3, 6, 3 · 4, 12, 12, 4 … row sums 0, 1, 4, 12, 32, 80, 192, 448, …
  A216973 (−∞, −1] nonnegative rational roots