sec(tanh(x)+tan(x))=1+4/2!*x^2+80/4!*x^4+4288/6!*x^6+426240/8!*x^8...
A013139
sec(tanh(x)+tan(x))=1+4/2!*x^2+80/4!*x^4+4288/6!*x^6+426240/8!*x^8...
Terms
- a(0) =1a(1) =4a(2) =80a(3) =4288a(4) =426240a(5) =67920896a(6) =15873495040
External references
- oeis: A013139