261885

Appears in sequences

• Numbers k such that sigma(k) = sigma(k+13).at n=27A015883
• a(n) = Sum_{k=1..n} A123706(n,k)*2^(k-1).at n=19A123707
• a(n) = Sum_{d|n} mu(n/d)*4^(d-1).at n=9A295505