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.

A152226 Binomial transform of A027826.

Original entry on oeis.org

1, 2, 5, 14, 42, 132, 428, 1416, 4745, 16034, 54505, 186166, 638538, 2198692, 7598624, 26350944, 91670946, 319825796, 1118686730, 3921801820, 13775938132, 48473233032, 170815501576, 602710956464, 2128981351316, 7527515059432, 26637591204996, 94331697697688
Offset: 0

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Author

Gary W. Adamson, Nov 29 2008

Keywords

Examples

			a(3) = 14 = (1, 1, 2, 4) dot (1, 3, 3, 1) = (1 + 3 + 6 + 4).
		

Crossrefs

Cf. A027826.

Programs

  • Maple
    b:= proc(n) option remember; add(`if`(k=0, 1,
          `if`(k::odd, 0, b(k/2)))*binomial(n, k), k=0..n)
        end:
    a:= n-> add(b(k)*binomial(n, k), k=0..n):
    seq(a(n), n=0..40);  # Alois P. Heinz, Jul 08 2015
  • Mathematica
    b[n_] := b[n] = Sum[If[k == 0, 1, If[OddQ[k], 0, b[k/2]]]*Binomial[n, k], {k, 0, n}];
    a[n_] := Sum[b[k]*Binomial[n, k], {k, 0, n}];
    Table[a[n], {n, 0, 40}] (* Jean-François Alcover, Jun 04 2018, from Maple *)

Formula

A007318 * A027826 as a vector. A027826 = [1, 1, 2, 4, 9, 21, 50, 120, 290,...].

Extensions

A-Number corrected by R. J. Mathar, Apr 04 2012