a(n) = (6^n/n!) * Product_{k=0..n-1} (6*k - 5).

A004995

a(n) = (6^n/n!) * Product_{k=0..n-1} (6*k - 5).

Terms

    a(0) =1a(1) =-30a(2) =-90a(3) =-1260a(4) =-24570a(5) =-560196a(6) =-14004900a(7) =-372130200a(8) =-10326613050a(9) =-296029574100

External references