Expansion of e.g.f. cosh(sinh(x))/exp(x).

Terms

a(0) =1a(1) =-1a(2) =2a(3) =-4a(4) =12a(5) =-36a(6) =128a(7) =-456a(8) =1872a(9) =-7888a(10) =37600a(11) =-184064a(12) =990784a(13) =-5444544a(14) =32333824a(15) =-195982208a(16) =1272660224a(17) =-8441139456a(18) =59527313920a(19) =-428299217920