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A100034 Bisection of A000081 (even part). 4
0, 1, 4, 20, 115, 719, 4766, 32973, 235381, 1721159, 12826228, 97055181, 743724984, 5759636510, 45007066269, 354426847597, 2809934352700, 22409533673568, 179655930440464, 1447023384581029, 11703780079612453, 95020085893954917, 774088023431472074 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

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):

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]; Table[a[n], {n, 0, 30}] (* Jean-Fran├žois Alcover, Mar 19 2014, after Alois P. Heinz *)

CROSSREFS

Cf. A000081, A100427, A299098.

Sequence in context: A316298 A291531 A171802 * A192924 A258664 A231539

Adjacent sequences:  A100031 A100032 A100033 * A100035 A100036 A100037

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane, Nov 20 2004

EXTENSIONS

More terms from Joshua Zucker, May 12 2006

STATUS

approved

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Last modified October 18 07:42 EDT 2019. Contains 328146 sequences. (Running on oeis4.)