a(n) = 1/(n + 1)^2 * Sum_{k = 1..n+1} (k^4)*binomial(n+1, k)^2.

A375177

a(n) = 1/(n + 1)^2 * Sum_{k = 1..n+1} (k^4)*binomial(n+1, k)^2.

Terms

    a(0) =1a(1) =5a(2) =26a(3) =134a(4) =670a(5) =3262a(6) =15540a(7) =72732a(8) =335478a(9) =1528670a(10) =6894316a(11) =30820660a(12) =136736236a(13) =602610764a(14) =2640266600a(15) =11508115320a(16) =49928451750a(17) =215717144670a(18) =928515985980

External references