70978

Appears in sequences

• Record-setting differences between adjacent elements of the Mian-Chowla sequence variant A051788.at n=41A080223
• Numbers k such that 10^k + 5*R_k + 2 is prime, where R_k = 11...1 is the repunit (A002275) of length k.at n=13A102937
• a(n) = Sum_{k=1..n} 2^(k/gcd(n,k) - 1).at n=17A338647