A355088 - OEIS

%I #8 Jun 18 2022 14:14:02

%S 1,1,7,199,21883,8916991,13027669147,66525761289919,

%T 1164200761777844203,68750129286493392353311,

%U 13532431689375421261723713787,8789916574829303798007959322784639,18685340957126032386127459367999667264523

%N E.g.f. A(x) satisfies A(x) = 1 + (exp(x) - 1) * A(3*x).

%F a(0) = 1; a(n) = Sum_{k=0..n-1} 3^k * binomial(n,k) * a(k).

%o (PARI) a_vector(n) = my(v=vector(n+1)); v[1]=1; for(i=1, n, v[i+1]=sum(j=0, i-1, 3^j*binomial(i, j)*v[j+1])); v;

%Y Cf. A000670, A352860.

%Y Cf. A355085, A355087.

%K nonn

%O 0,3

%A _Seiichi Manyama_, Jun 18 2022