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

Terms

a(0) =1a(1) =2a(2) =6a(3) =22a(4) =98a(5) =516a(6) =3172a(7) =22436a(8) =180252a(9) =1624888a(10) =16258376a(11) =178877832a(12) =2146674136a(13) =27907332272a(14) =390705042288