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A023429 Generalized Catalan Numbers. 1
1, 1, 1, 1, 1, 1, 1, 2, 4, 7, 11, 17, 27, 44, 73, 122, 204, 340, 566, 945, 1586, 2674, 4521, 7656, 12982, 22047, 37509, 63934, 109166, 186685, 319679, 548091, 940819, 1616830, 2781706, 4790949, 8259748, 14253480, 24618561, 42557378 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,8

LINKS

Alois P. Heinz, Table of n, a(n) for n = 0..1000

MAPLE

a:= proc(n) option remember;

      `if`(n=0, 1, a(n-1) +add(a(k)*a(n-4-k), k=3..n-4))

    end:

seq(a(n), n=0..50);  # Alois P. Heinz, May 07 2011

MATHEMATICA

Clear[ a ]; a[ 0 ]=1; a[ n_Integer ] := a[ n ]=a[ n-1 ]+Sum[ a[ k ]*a[ n-4-k ], {k, 3, n-4} ];

CROSSREFS

Cf. A000108, A001006, A004148, A006318.

Sequence in context: A006999 A005252 A023430 * A023428 A093911 A152398

Adjacent sequences:  A023426 A023427 A023428 * A023430 A023431 A023432

KEYWORD

nonn,easy

AUTHOR

Olivier Gérard

STATUS

approved

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Last modified October 19 17:55 EDT 2018. Contains 316376 sequences. (Running on oeis4.)