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A023430 Generalized Catalan Numbers. 1
1, 1, 1, 1, 1, 1, 1, 1, 2, 4, 7, 11, 17, 27, 44, 72, 118, 194, 320, 528, 871, 1439, 2385, 3965, 6605, 11017, 18399, 30771, 51538, 86440, 145165, 244085, 410890, 692442, 1168114, 1972470 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,9

LINKS

Table of n, a(n) for n=0..35.

MAPLE

A023430 := proc(n)

    option remember;

    if n = 0 then

        1;

    else

        procname(n-1)+add(procname(k)*procname(n-4-k), k=4..n-4) ;

    end if;

end proc: # R. J. Mathar, May 01 2015

MATHEMATICA

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

CROSSREFS

Cf. A000108, A001006, A004148, A006318.

Sequence in context: A289010 A006999 A005252 * A023429 A023428 A093911

Adjacent sequences:  A023427 A023428 A023429 * A023431 A023432 A023433

KEYWORD

nonn,easy

AUTHOR

Olivier Gérard

STATUS

approved

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Last modified October 20 15:03 EDT 2018. Contains 316388 sequences. (Running on oeis4.)