a(n) = (1/2) * Sum_{k=0..n} binomial(7*n+5,7*k+2).

A387818

a(n) = (1/2) * Sum_{k=0..n} binomial(7*n+5,7*k+2).

Terms

    a(0) =5a(1) =143a(2) =46759a(3) =4219605a(4) =648968617a(5) =76352795259

External references