G.f.: 1 + 1!*x/(1 + 2!*x^2/(1 + 3!*x^3/(1 + 4!*x^4/(1 + 5!*x^5/(1 + ...))))).

Terms

a(0) =1a(1) =1a(2) =0a(3) =-2a(4) =0a(5) =4a(6) =12a(7) =-8a(8) =-48a(9) =-56a(10) =-144a(11) =400a(12) =1200a(13) =1792a(14) =960a(15) =16864a(16) =-34560a(17) =-170816a(18) =-320064a(19) =-632960a(20) =-869376a(21) =-15780224a(22) =30636288a(23) =144493312a(24) =360770304a(25) =738095104a(26) =2382729216a(27) =6661606912a(28) =81815537664a(29) =-152267942912