A013329 arcsin(exp(x)-sec(x))=x+2/3!*x^3-4/4!*x^4+20/5!*x^5-120/6!*x^6...

1, 0, 2, -4, 20, -120, 632, -6704, 44480, -630240, 5566112, -91544704, 1063375040, -19258162560, 283305867392, -5578129589504, 99671066259200, -2135174387566080, 44678363702761472, -1044242762736047104