G.f.: A(x) = Sum_{n>=0} ( Sum_{k>=1} (2^n*2^k*x)^k/k )^n / n!, a power series in x with integer coefficients.
A156631
G.f.: A(x) = Sum_{n>=0} ( Sum_{k>=1} (2^n*2^k*x)^k/k )^n / n!, a power series in x with integer coefficients.
Terms
- a(0) =1a(1) =4a(2) =64a(3) =3072a(4) =466944a(5) =283115520a(6) =814634500096
External references
- oeis: A156631