a(n) = 4*binomial(11*n+4,n)/(11*n+4).

A234870

a(n) = 4*binomial(11*n+4,n)/(11*n+4).

Terms

    a(0) =1a(1) =4a(2) =50a(3) =840a(4) =16215a(5) =339416a(6) =7492342a(7) =171714400a(8) =4046995095a(9) =97464474800

External references