sec(tanh(x)*cos(x))=1+1/2!*x^2-15/4!*x^4+57/6!*x^6+13825/8!*x^8...

A012691

sec(tanh(x)*cos(x))=1+1/2!*x^2-15/4!*x^4+57/6!*x^6+13825/8!*x^8...

Terms

    a(0) =1a(1) =1a(2) =-15a(3) =57a(4) =13825a(5) =-869711a(6) =-32509455a(7) =15341387817

External references