a(n) = Sum_{k=0..n} (1-i)^k * (1+i)^(n-k) * binomial(n+2,k) * binomial(n+2,n-k), where i is the imaginary unit.
A387402
a(n) = Sum_{k=0..n} (1-i)^k * (1+i)^(n-k) * binomial(n+2,k) * binomial(n+2,n-k), where i is the imaginary unit.
Terms
- a(0) =1a(1) =6a(2) =32a(3) =160a(4) =780a(5) =3752a(6) =17920a(7) =85248a(8) =404640a(9) =1918400a(10) =9090048a(11) =43064320a(12) =204032192a(13) =966887040a(14) =4583424000a(15) =21735350272a(16) =103114538496a(17) =489392157696
External references
- oeis: A387402