E.g.f.: exp(x-sqrt(1-x^2)+1).

Terms

a(0) =1a(1) =1a(2) =2a(3) =4a(4) =13a(5) =41a(6) =211a(7) =967a(8) =7274a(9) =44578a(10) =449551a(11) =3456641a(12) =43883797a(13) =405589549a(14) =6212792678a(15) =67022223556