sec(arcsinh(x)+arctan(x))=1+4/2!*x^2+56/4!*x^4+1990/6!*x^6...

A013113

sec(arcsinh(x)+arctan(x))=1+4/2!*x^2+56/4!*x^4+1990/6!*x^6...

Terms

    a(0) =1a(1) =4a(2) =56a(3) =1990a(4) =130280a(5) =13814650a(6) =2137954100a(7) =457685029750

External references