Expansion of e.g.f. arctanh(log(1 + x)).

Terms

a(0) =0a(1) =1a(2) =-1a(3) =4a(4) =-18a(5) =118a(6) =-930a(7) =8888a(8) =-98504a(9) =1248784a(10) =-17790480a(11) =281590032a(12) =-4901447232a(13) =93064850448