sech(arctan(x)+tan(x))=1-4/2!*x^2+80/4!*x^4-4384/6!*x^6+451328/8!*x^8...
A013008
sech(arctan(x)+tan(x))=1-4/2!*x^2+80/4!*x^4-4384/6!*x^6+451328/8!*x^8...
Terms
- a(0) =1a(1) =-4a(2) =80a(3) =-4384a(4) =451328a(5) =-74726784a(6) =18162914304
External references
- oeis: A013008