a(n) = (1/2) * Sum_{k=0..n-1} binomial(4*n,4*k+2).
A387742
a(n) = (1/2) * Sum_{k=0..n-1} binomial(4*n,4*k+2).
Terms
- a(0) =0a(1) =3a(2) =28a(3) =528a(4) =8128a(5) =131328a(6) =2096128a(7) =33558528a(8) =536854528a(9) =8590000128a(10) =137438691328
External references
- oeis: A387742