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