E.g.f. sech(log(x+1)/exp(x)).

Terms

a(0) =1a(1) =0a(2) =-1a(3) =9a(4) =-54a(5) =210a(6) =510a(7) =-24500a(8) =355544a(9) =-3310776a(10) =7970880a(11) =511460048a(12) =-14772993312a(13) =247420878848