a(n) = [x^n] Product_{k=0..n} (1 + (3*n+k)*x).

A382349

a(n) = [x^n] Product_{k=0..n} (1 + (3*n+k)*x).

Terms

    a(0) =1a(1) =7a(2) =146a(3) =4578a(4) =189144a(5) =9660840a(6) =586813968a(7) =41283943344

External references