sech(arcsin(arctanh(x)))=1-1/2!*x^2-7/4!*x^4-169/6!*x^6-9199/8!*x^8...

A012145

sech(arcsin(arctanh(x)))=1-1/2!*x^2-7/4!*x^4-169/6!*x^6-9199/8!*x^8...

Terms

    a(0) =1a(1) =-1a(2) =-7a(3) =-169a(4) =-9199a(5) =-915441a(6) =-146524599a(7) =-34565815257

External references