31874997

Appears in sequences

• cos(sec(x)*arctan(x))=1-1/2!*x^2-3/4!*x^4-165/6!*x^6+1337/8!*x^8...at n=6A012806
• Expansion of e.g.f.: exp(sech(x)*arctanh(x))=1+x+1/2!*x^2-3/4!*x^4+20/5!*x^5+165/6!*x^6...at n=12A012882