[ exp(15/19)*n! ].

Terms

a(0) =2a(1) =4a(2) =13a(3) =52a(4) =264a(5) =1585a(6) =11099a(7) =88794a(8) =799147a(9) =7991477a(10) =87906255a(11) =1054875070a(12) =13713375910a(13) =191987262753