sec(sec(x)-sech(x)) = 1+12/4!*x^4+15232/8!*x^8+128432832/12!*x^12...

A013514

sec(sec(x)-sech(x)) = 1+12/4!*x^4+15232/8!*x^8+128432832/12!*x^12...

Terms

    a(0) =1a(1) =12a(2) =15232a(3) =128432832

External references