E.g.f. exp(x)*BesselI(1,4*x)/2.

Terms

a(0) =0a(1) =1a(2) =2a(3) =15a(4) =52a(5) =285a(6) =1206a(7) =6027a(8) =27560a(9) =134073a(10) =633130a(11) =3062279a(12) =14676828a(13) =71045845a(14) =343195230a(15) =1665555075a(16) =8084777040a(17) =39343835505a(18) =191627687250a(19) =934855945215