sech(tan(arcsinh(x)))=1-1/2!*x^2+1/4!*x^4-1/6!*x^6+449/8!*x^8...
A012169
sech(tan(arcsinh(x)))=1-1/2!*x^2+1/4!*x^4-1/6!*x^6+449/8!*x^8...
Terms
- a(0) =1a(1) =-1a(2) =1a(3) =-1a(4) =449a(5) =-31681a(6) =3077185a(7) =-445157441a(8) =87981830785
External references
- oeis: A012169