sinh(sec(x)-sech(x))=2/2!*x^2+242/6!*x^6+438722/10!*x^10...

A013509

sinh(sec(x)-sech(x))=2/2!*x^2+242/6!*x^6+438722/10!*x^10...

Terms

    a(0) =2a(1) =242a(2) =438722a(3) =3496736882

External references