Imaginary part of g.f. C(x) that satisfies: C(x) = 1 + x*C(I*x)^2.

Terms

a(0) =2a(1) =-4a(2) =2a(3) =-4a(4) =-20a(5) =56a(6) =-126a(7) =-4a(8) =308a(9) =-696a(10) =5444a(11) =7224a(12) =-7272a(13) =-14224a(14) =-191022a(15) =-450404a(16) =39524a(17) =2309416a(18) =5059084a(19) =20045736a(20) =18158632a(21) =-170205936a(22) =-18475212a(23) =-725028200a(24) =-1746739960a(25) =9540210896a(26) =-10852826168a(27) =16441084912a(28) =107790254896a(29) =-422324078368