a(n) = n! * [x^n] (x * tanh(x) * sech(x)) / 2.

Terms

a(0) =0a(1) =0a(2) =1a(3) =0a(4) =-10a(5) =0a(6) =183a(7) =0a(8) =-5540a(9) =0a(10) =252605a(11) =0a(12) =-16216590a(13) =0a(14) =1395526867a(15) =0a(16) =-155132097160a(17) =0a(19) =0a(21) =0a(23) =0a(25) =0a(27) =0a(29) =0