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

Terms

a(0) =1a(1) =0a(2) =0a(3) =2a(4) =2a(5) =2a(6) =42a(7) =142a(8) =366a(9) =3082a(10) =18626a(11) =86990a(12) =596158a(13) =4485626a(14) =30214498a(15) =224897662a(16) =1871664190a(17) =15587540042a(18) =134045407458