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

Terms

a(0) =1a(1) =0a(2) =0a(3) =-3a(4) =11a(5) =-30a(6) =194a(7) =-1785a(8) =13957a(9) =-113148a(10) =1143284a(11) =-13131855a(12) =156950639a(13) =-2005222362a(14) =28119703702a(15) =-424785970245