a(n) = (6^n/n!) * Product_{k=0..n-1} (6*k + 7).

A004997

a(n) = (6^n/n!) * Product_{k=0..n-1} (6*k + 7).

Terms

    a(0) =1a(1) =42a(2) =1638a(3) =62244a(4) =2334150a(5) =86830380a(6) =3212724060a(7) =118411829640

External references