111973685

Appears in sequences

• tan(arcsin(tan(x))) = x+5/3!*x^3+121/5!*x^5+6845/7!*x^7+698161/9!*x^9...at n=5A012077
• Expansion of e.g.f. exp(arctanh(tan(x))).at n=11A012259
• Hafnian of a +/-1 array.at n=11A202038