cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A143639 E.g.f. satisfies: A(x) = exp(x*A(((x+1)^8-1)/8)).

Original entry on oeis.org

1, 1, 3, 37, 713, 20931, 900067, 51768739, 3815631297, 351259985449, 39429531406511, 5287999813256799, 833815716731955817, 152569133029591977895, 32033950906843181020467, 7643291957710224206903131, 2055010408602517321146955553, 618032357523179035120686532401
Offset: 0

Views

Author

Alois P. Heinz, Aug 27 2008

Keywords

Crossrefs

Cf. 8th column of A143632.

Programs

  • Maple
    A:= proc(n,k::nonnegint) option remember; if n<=0 or k=0 then 1 else A(n-1,k)(((x+1)^k-1)/k) fi; unapply(convert(series(exp(x*%), x,n+1), polynom), x) end: a:= n-> coeff(A(n,8)(x), x,n)*n!: seq(a(n), n=0..20);
  • Mathematica
    A[n_, k_] := Module[{f}, f[x_] = If[n <= 0 || k == 0, 1, A[n-1, k][((x+1)^k-1)/k]]; Normal[Series[Exp[x*f[x]], { x, 0, n+1}]] /. x -> #]&; a[n_] := Coefficient[A[n, 8][x], x, n]*n!; Table[a[n], {n, 0, 21}] (* Jean-François Alcover, Feb 14 2014, after Maple *)