sech(sec(x)*arctan(x))=1-1/2!*x^2+1/4!*x^4-145/6!*x^6+6977/8!*x^8...
A012813
sech(sec(x)*arctan(x))=1-1/2!*x^2+1/4!*x^4-145/6!*x^6+6977/8!*x^8...
Terms
- a(0) =1a(1) =-1a(2) =1a(3) =-145a(4) =6977a(5) =-568865a(6) =80708417a(7) =-14347965489
External references
- oeis: A012813