sec(arctanh(x)*arctan(x)) = 1+12/4!*x^4+20048/8!*x^8+255870912/12!*x^12...

A012736

sec(arctanh(x)*arctan(x)) = 1+12/4!*x^4+20048/8!*x^8+255870912/12!*x^12...

Terms

    a(0) =1a(1) =12a(2) =20048a(3) =255870912

External references