E.g.f. exp(5x)/(1-x).

Terms

a(0) =1a(1) =6a(2) =37a(3) =236a(4) =1569a(5) =10970a(6) =81445a(7) =648240a(8) =5576545a(9) =52142030a(10) =531185925a(11) =5891873300a(12) =70946620225a(13) =923526766050