G.f. A(x) satisfies [x^n] A(x)^prime(n) = 0 for n > 1.

Terms

a(0) =1a(1) =1a(2) =-1a(3) =2a(4) =-5a(5) =13a(6) =-31a(7) =48a(8) =129a(9) =-2035a(10) =12963a(11) =-20703a(12) =-782282a(13) =14675113a(14) =-177056253a(15) =1716591959a(16) =-14243243451a(17) =103606488776a(18) =-627394591646