sech(arcsinh(x)*tan(x))=1-12/4!*x^4-120/6!*x^6+1680/8!*x^8...

A012621

sech(arcsinh(x)*tan(x))=1-12/4!*x^4-120/6!*x^6+1680/8!*x^8...

Terms

    a(0) =1a(1) =0a(2) =-12a(3) =-120a(4) =1680a(5) =367680a(6) =12095424a(7) =-560956032a(8) =-447394871040

External references