A034751 Dirichlet convolution of 3^(n-1) with itself.

1, 6, 18, 63, 162, 540, 1458, 4536, 13203, 39852, 118098, 356238, 1062882, 3193020, 9567396, 28711665, 86093442, 258324066, 774840978, 2324645406, 6973581924, 20921060700, 62762119218, 188287473024, 564859079523, 1694580407532

Offset

1,2

Links

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

Formula

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

G.f.: Sum_{k>=1} 3^(k-1)*x^k / (1 - 3*x^k). - Ilya Gutkovskiy, Sep 22 2020

Mathematica

Table[Sum[3^(d + n/d - 2), {d, Divisors[n]}], {n, 1, 30}] (* Vaclav Kotesovec, Sep 10 2019 *)

Crossrefs

Cf. A034719.

Sequence in context: A334330 A144706 A074427 * A200151 A000623 A304941

Adjacent sequences: A034748 A034749 A034750 * A034752 A034753 A034754

Keyword

nonn

Author

Erich Friedman

Status

approved