a(n) = (3^n/n!) * Product_{k=0..n-1} (3*k + 5).
A004992
a(n) = (3^n/n!) * Product_{k=0..n-1} (3*k + 5).
Terms
- a(0) =1a(1) =15a(2) =180a(3) =1980a(4) =20790a(5) =212058a(6) =2120580a(7) =20902860a(8) =203802885a(9) =1970094555a(10) =18912907728a(11) =180532301040
External references
- oeis: A004992