A368018 Expansion of e.g.f. exp(exp(2*x) - exp(3*x)).

1, -1, -4, -5, 57, 548, 1967, -13561, -302718, -2589819, -2709911, 300801642, 5531279773, 48708116819, -142678610012, -13947271486097, -277586590571059, -2741155101562764, 15789174378252979, 1332483468802350235, 31222229349684528898, 380895661222461566625

Offset: 0

Author

Seiichi Manyama, Dec 08 2023

Keywords

• sign

Crossrefs

Cf. A355381.

Programs

PARI

a_vector(n) = my(v=vector(n+1)); v[1]=1; for(i=1, n, v[i+1]=sum(j=1, i, (2^j-3^j)*binomial(i-1, j-1)*v[i-j+1])); v;

Formula

a(0) = 1; a(n) = Sum_{k=1..n} (2^k - 3^k) * binomial(n-1,k-1) * a(n-k).