a(n) = (3*n+4)*(n+3)!/24.
A005460
a(n) = (3*n+4)*(n+3)!/24.
Terms
- a(0) =1a(1) =7a(2) =50a(3) =390a(4) =3360a(5) =31920a(6) =332640a(7) =3780000a(8) =46569600a(9) =618710400a(10) =8821612800a(11) =134399865600
External references
- oeis: A005460
A005460
a(n) = (3*n+4)*(n+3)!/24.