Expansion of cosh(tan(x)*x).A009166Expansion of cosh(tan(x)*x).Terms a(0) =1a(1) =0a(2) =12a(3) =240a(4) =9296a(5) =558720a(6) =47965632a(7) =5537249536a(8) =823842474240External referencesoeis: A009166