cos(cos(x)*arctan(x))=1-1/2!*x^2+21/4!*x^4-645/6!*x^6+34153/8!*x^8...

A012501

cos(cos(x)*arctan(x))=1-1/2!*x^2+21/4!*x^4-645/6!*x^6+34153/8!*x^8...

Terms

    a(0) =1a(1) =-1a(2) =21a(3) =-645a(4) =34153a(5) =-2966505a(6) =380114493a(7) =-67244074989

External references