A034768 Dirichlet convolution of Catalan numbers with themselves.

1, 2, 4, 11, 28, 88, 264, 868, 2864, 9752, 33592, 117676, 416024, 1486064, 5348936, 19390573, 70715340, 259292608, 955277400, 3534536244, 13128241368, 48932567632, 182965127280, 686119347008, 2579808294844, 9723893218928

Offset

1,2

Links

Table of n, a(n) for n=1..26.

Formula

a(n) ~ 2^(2*n-1) / (sqrt(Pi) * n^(3/2)). - Vaclav Kotesovec, Sep 11 2019

Mathematica

Table[Sum[CatalanNumber[n/d - 1]*CatalanNumber[d - 1], {d, Divisors[n]}], {n, 1, 25}] (* Vaclav Kotesovec, Sep 10 2019 *)

Crossrefs

Sequence in context: A151425 A148135 A363454 * A148136 A148137 A148138

Adjacent sequences: A034765 A034766 A034767 * A034769 A034770 A034771

Keyword

nonn

Author

Erich Friedman

Status

approved