E.g.f.: A(x) = 1/(3-exp(x)-exp(x^2)).

Terms

a(0) =1a(1) =1a(2) =5a(3) =25a(4) =207a(5) =1901a(6) =22323a(7) =295597a(8) =4554763a(9) =78201805a(10) =1499474883a(11) =31541086853a(12) =724817679171