a(n) = Sum_{k=0..n} (1-i)^k * (1+i)^(n-k) * binomial(n+1,k) * binomial(n+1,n-k), where i is the imaginary unit.
A387401
a(n) = Sum_{k=0..n} (1-i)^k * (1+i)^(n-k) * binomial(n+1,k) * binomial(n+1,n-k), where i is the imaginary unit.
Terms
- a(0) =1a(1) =4a(2) =18a(3) =80a(4) =360a(5) =1632a(6) =7448a(7) =34176a(8) =157536a(9) =728960a(10) =3384128a(11) =15754752a(12) =73525504a(13) =343870464a(14) =1611288960a(15) =7562801152a(16) =35550504448a(17) =167339022336a(18) =788643765248
External references
- oeis: A387401