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Dirichlet convolution of 3^(n-1) with Catalan numbers.
0

%I #7 Sep 11 2019 05:00:01

%S 1,4,11,35,95,300,861,2658,8009,24668,75845,236401,739453,2338348,

%T 7457697,24047361,78404391,258796668,865059189,2929559709,10050907467,

%U 34926729660,122863623249,437203156566,1572333684939,5709236166372

%N Dirichlet convolution of 3^(n-1) with Catalan numbers.

%F a(n) ~ 2^(2*n-2) / (sqrt(Pi) * n^(3/2)). - _Vaclav Kotesovec_, Sep 11 2019

%t Table[Sum[CatalanNumber[n/d - 1]*3^(d - 1), {d, Divisors[n]}], {n, 1, 25}] (* _Vaclav Kotesovec_, Sep 10 2019 *)

%K nonn

%O 1,2

%A _Erich Friedman_