256122

Appears in sequences

• arctan(arctan(x)*arcsin(x))=2/2!*x^2-4/4!*x^4-82/6!*x^6+3096/8!*x^8...at n=4A012435
• a(n) = Sum_{k=1..n} sigma( (n/gcd(k,n))^4 ).at n=11A373000