A385651 E.g.f. A(x) satisfies A(x) = exp( x*(A(x) + A(2*x))^3 ).

1, 8, 640, 150272, 81879040, 97446821888, 252536538529792, 1441194498488532992, 18238881125752291459072, 511646632486244583515095040, 31662959021226253504069431721984, 4295217009165735294411016058313900032, 1268984197722535033624735101886101792489472

Offset: 0

Author

Seiichi Manyama, Jul 06 2025

Keywords

• nonn

Crossrefs

Cf. A385619, A385650.

Cf. A168601, A385649.

Formula

a(0) = 1; a(n) = (n-1)! * Sum_{i, j, k, l>=0 and i+j+k+l=n-1} (n-i) * (2^j+1) * (2^k+1) * (2^l+1) * a(i) * a(j) * a(k) * a(l)/(i! * j! * k! * l!).