a(n) = multinomial(2*n+3; 3, 2, 2, ..., 2) (n times '2').
A327411
a(n) = multinomial(2*n+3; 3, 2, 2, ..., 2) (n times '2').
Terms
- a(0) =1a(1) =10a(2) =210a(3) =7560a(4) =415800a(5) =32432400a(6) =3405402000a(7) =463134672000
External references
- oeis: A327411