65588

Appears in sequences

• Numbers n such that sigma(n) - n = sigma(n') - n', where n' is the arithmetic derivative of n.at n=9A239726
• Number of length n+3 0..4 arrays with no four elements in a row with pattern aabb (possibly a=b) and new values 0..4 introduced in 0..4 order.at n=6A242545
• T(n,k)=Number of length n+3 0..k arrays with no four elements in a row with pattern aabb (possibly a=b) and new values 0..k introduced in 0..k order.at n=51A242549
• a(1) = 2; for n > 1, a(n) is the least positive number not yet in the sequence such that Sum_{k=1..n} a(k) divides Sum_{k=1..n} a(k)^2.at n=48A318358
• a(n) = Sum_{d|n} d^phi(n/d).at n=33A344484