Expansion of cosh(tanh(x))/exp(x).

Terms

a(0) =1a(1) =-1a(2) =2a(3) =-4a(4) =0a(5) =24a(6) =8a(7) =-456a(8) =192a(9) =11264a(10) =-20480a(11) =-289664a(12) =1837696a(13) =-3000960a(14) =-187743488a(15) =2697206272a(16) =22698672128a(17) =-625547980800