Expansion of e.g.f. cosh( 3 * (exp(x) - 1) ).

Terms

a(0) =1a(1) =0a(2) =9a(3) =27a(4) =144a(5) =945a(6) =6273a(7) =44226a(8) =339399a(9) =2796795a(10) =24387786a(11) =223853355a(12) =2159078445a(13) =21827316888a(14) =230536050165