cos(sec(x)*arctanh(x))=1-1/2!*x^2-19/4!*x^4-565/6!*x^6-24743/8!*x^8...

A012845

cos(sec(x)*arctanh(x))=1-1/2!*x^2-19/4!*x^4-565/6!*x^6-24743/8!*x^8...

Terms

    a(0) =1a(1) =-1a(2) =-19a(3) =-565a(4) =-24743a(5) =-1450985a(6) =-100090043a(7) =-5608180253a(8) =703874231473

External references