log(cos(arcsinh(x))) = -1/2!*x^2+2/4!*x^4-40/6!*x^6+1360/8!*x^8...

A012241

log(cos(arcsinh(x))) = -1/2!*x^2+2/4!*x^4-40/6!*x^6+1360/8!*x^8...

Terms

    a(0) =-1a(1) =2a(2) =-40a(3) =1360a(4) =-87680a(5) =8723200a(6) =-1254323200a(7) =245463296000

External references