A034764 Dirichlet convolution of sigma(n) with Catalan numbers.

1, 4, 6, 15, 20, 64, 140, 466, 1451, 4928, 16808, 58986, 208026, 743328, 2674532, 9696213, 35357688, 129649324, 477638720, 1767277964, 6564120996, 24466317456, 91482563664, 343059792196, 1289904147439, 4861947025544

Offset

1,2

Links

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

Formula

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

Mathematica

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

Crossrefs

Sequence in context: A034771 A294457 A266883 * A119034 A100911 A346297

Adjacent sequences: A034761 A034762 A034763 * A034765 A034766 A034767

Keyword

nonn

Author

Erich Friedman

Status

approved