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A030033 a(n+1) = Sum_{k = 0..floor(2*n/3)} a(k)*a(n-k) for n >= 0 with a(0) = 1. 1
1, 1, 1, 2, 4, 7, 15, 34, 72, 165, 387, 861, 2039, 4894, 11256, 27085, 66021, 156347, 381720, 940211, 2261208, 5578659, 13846756, 33654950, 83539418, 208608556, 512069441, 1278522424, 3207377196, 7925966000 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

LINKS

Seiichi Manyama, Table of n, a(n) for n = 0..1000

MAPLE

a := proc(n) local k; option remember;

if n = 0 then 1;

else add(a(k)*a(n - 1 - k), k = 0 .. floor(2/3*n - 2/3));

end if;

end proc;

seq(a(n), n = 0..30); # Petros Hadjicostas, Nov 07 2019

CROSSREFS

Cf. A000992, A030032, A030037.

Sequence in context: A358824 A072964 A247291 * A280031 A135131 A032363

Adjacent sequences: A030030 A030031 A030032 * A030034 A030035 A030036

KEYWORD

nonn

AUTHOR

N. J. A. Sloane

EXTENSIONS

Name edited by Petros Hadjicostas, Nov 07 2019

STATUS

approved

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Last modified March 22 18:49 EDT 2023. Contains 361433 sequences. (Running on oeis4.)