sech(sin(arcsinh(x)))=1-1/2!*x^2+13/4!*x^4-421/6!*x^6+25817/8!*x^8...

A012045

sech(sin(arcsinh(x)))=1-1/2!*x^2+13/4!*x^4-421/6!*x^6+25817/8!*x^8...

Terms

    a(0) =1a(1) =-1a(2) =13a(3) =-421a(4) =25817a(5) =-2565961a(6) =375964645a(7) =-76201822061

External references