a(n) = (1/(5*n+3)) * Sum_{k=0..n} (5*k+3) * binomial(5*n+3,n-k).
A390779
a(n) = (1/(5*n+3)) * Sum_{k=0..n} (5*k+3) * binomial(5*n+3,n-k).
Terms
- a(0) =1a(1) =4a(2) =27a(3) =218a(4) =1933a(5) =18168a(6) =177717a(7) =1789872a(8) =18432897a(9) =193200500a(10) =2054074838a(11) =22097723916a(12) =240098265351
External references
- oeis: A390779