A034735 Dirichlet convolution of b_n=2^(n-1) with c_n=3^(n-1).

1, 5, 13, 41, 97, 305, 793, 2393, 6853, 20405, 60073, 179957, 535537, 1604165, 4799821, 14386649, 43112257, 129286385, 387682633, 1162827737, 3487836469, 10462571525, 31385253913, 94151940581, 282446314993, 847323239045, 2541932965741, 7625734923497, 22877060890417

Offset

1,2

Links

Robert Israel, Table of n, a(n) for n = 1..2094

Formula

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

G.f.: Sum_{k>=1} 3^(k-1)*x^k / (1 - 2*x^k). - Ilya Gutkovskiy, Sep 22 2020

Maple

f:= n -> add(2^d * 3^(n/d)/6, d = numtheory:-divisors(n)):
map(f, [$1..50]); # Robert Israel, Jun 25 2020

Mathematica

Table[Sum[2^(d - 1)*3^(n/d - 1), {d, Divisors[n]}], {n, 1, 30}] (* Vaclav Kotesovec, Sep 11 2019 *)

Prog

(PARI) a(n) = sumdiv(n, d, 2^(d-1) * 3^(n/d-1) ); /* Joerg Arndt, Apr 14 2013 */

Crossrefs

Cf. A038039.

Sequence in context: A100210 A359730 A080267 * A305464 A200150 A287017

Adjacent sequences: A034732 A034733 A034734 * A034736 A034737 A034738

Keyword

nonn

Author

Erich Friedman

Status

approved