a(n) = (1/3) * Sum_{k=0..n-1} binomial(6*n,6*k+2).
A387746
a(n) = (1/3) * Sum_{k=0..n-1} binomial(6*n,6*k+2).
Terms
- a(0) =0a(1) =5a(2) =187a(3) =15657a(4) =902543a(5) =60449485a(6) =3796225347a(7) =244917048017
External references
- oeis: A387746
A387746
a(n) = (1/3) * Sum_{k=0..n-1} binomial(6*n,6*k+2).