71665

Appears in sequences

• Consider a number of k digits n = d_(k)*10^(k-1) + d_(k-1)*10^(k-2) + … + d_(2)*10 + d_(1). Sequence lists the numbers n such that Sum_{i=1..k-1}{phi(Sum_{j=1..i}{d_(j)*10^(j-1)})} = Sum_{i=1..k-1}{sigma(Sum_{j=1..i}{d_(k-j+1)*10^(i-j)})} (see example below).at n=23A244069
• Numbers n such that 2*n*3^n + 1 is prime.at n=33A266694
• Let p = n-th prime == 3 mod 8; a(n) = sum of quadratic residues mod p that are < p/2.at n=45A282721