a(n) = Sum_{k=0..n} binomial(5*n+3,5*k+1).

A387812

a(n) = Sum_{k=0..n} binomial(5*n+3,5*k+1).

Terms

    a(0) =3a(1) =36a(2) =1807a(3) =50559a(4) =1698458a(5) =53457121a(6) =1720537327a(7) =54947296924

External references