E.g.f. (1+arctan(x))^arctan(x).

Terms

a(0) =1a(1) =0a(2) =2a(3) =-3a(4) =4a(5) =-30a(6) =162a(7) =-252a(8) =400a(9) =-27912a(10) =200744a(11) =705672a(12) =-4202296a(13) =-223340208a(14) =1418238416a(15) =29398266888a(16) =-114981277184