a(n) = (3*n)! * [z^(3*n)] exp(exp(z)/3 + 2*exp(-z/2)*cos(z*sqrt(3)/2)/3 - 1).
A291973
a(n) = (3*n)! * [z^(3*n)] exp(exp(z)/3 + 2*exp(-z/2)*cos(z*sqrt(3)/2)/3 - 1).
Terms
- a(0) =1a(1) =1a(2) =11a(3) =365a(4) =25323a(5) =3068521a(6) =583027547a(7) =161601254725
External references
- oeis: A291973