cos(sec(x)*arcsinh(x))=1-1/2!*x^2-7/4!*x^4-145/6!*x^6-2063/8!*x^8...

A012826

cos(sec(x)*arcsinh(x))=1-1/2!*x^2-7/4!*x^4-145/6!*x^6-2063/8!*x^8...

Terms

    a(0) =1a(1) =-1a(2) =-7a(3) =-145a(4) =-2063a(5) =-128705a(6) =5154217a(7) =-510686033a(8) =254809389793

External references