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

Terms

a(0) =1a(1) =-1a(2) =2a(3) =-2a(4) =0a(5) =8a(6) =8a(7) =-184a(8) =192a(9) =5568a(10) =-20480a(11) =-231552a(12) =1837696a(13) =11751296a(14) =-187743488a(15) =-596164352a(16) =22698672128a(17) =4342886400