Numerator of the coefficient [x^(2n)] in the Taylor series sec(cosec(x) - cosech(x)).

A013535

Numerator of the coefficient [x^(2n)] in the Taylor series sec(cosec(x) - cosech(x)).

Terms

    a(0) =1a(1) =1a(2) =5a(3) =5449a(4) =6973a(5) =518819753a(6) =1489058191a(7) =293416964947

External references