sech(arctan(sin(x)))=1-1/2!*x^2+17/4!*x^4-721/6!*x^6+58337/8!*x^8...

A012193

sech(arctan(sin(x)))=1-1/2!*x^2+17/4!*x^4-721/6!*x^6+58337/8!*x^8...

Terms

    a(0) =1a(1) =-1a(2) =17a(3) =-721a(4) =58337a(5) =-7657441a(6) =1482169457a(7) =-396854618161

External references