cosh(sec(x)*arctan(x))=1+1/2!*x^2+5/4!*x^4+205/6!*x^6+2473/8!*x^8...

A012811

cosh(sec(x)*arctan(x))=1+1/2!*x^2+5/4!*x^4+205/6!*x^6+2473/8!*x^8...

Terms

    a(0) =1a(1) =1a(2) =5a(3) =205a(4) =2473a(5) =475385a(6) =-2814227a(7) =5900398725a(8) =-532397600303

External references