A100427 Bisection of A000081 (odd part).

1, 2, 9, 48, 286, 1842, 12486, 87811, 634847, 4688676, 35221832, 268282855, 2067174645, 16083734329, 126186554308, 997171512998, 7929819784355, 63411730258053, 509588049810620, 4113254119923150, 33333125878283632, 271097737169671824, 2212039245722726118

Offset

0,2

Links

Alois P. Heinz, Table of n, a(n) for n = 0..400

Maple

with(numtheory):
b:= proc(n) option remember; local d, j; `if`(n<2, n,
      (add(add(d*b(d), d=divisors(j))*b(n-j), j=1..n-1))/(n-1))
    end:
a:= n-> b(2*n+1):
seq(a(n), n=0..50);  # Alois P. Heinz, May 16 2013

Mathematica

b[n_] := b[n] = If[n <= 1, n, Sum[Sum[d*b[d], {d, Divisors[j]}]*b[n-j], {j, 1, n-1}]/(n-1)]; a[n_] := b[2*n+1]; Table[a[n], {n, 0, 30}] (* Jean-François Alcover, Mar 19 2014, after Alois P. Heinz *)

Crossrefs

Cf. A000081, A100034, A299113.

Sequence in context: A365133 A171803 A368961 * A214404 A074143 A198892

Adjacent sequences: A100424 A100425 A100426 * A100428 A100429 A100430

Keyword

nonn,easy

Author

N. J. A. Sloane, Nov 20 2004

Extensions

More terms from Joshua Zucker, May 12 2006

Status

approved