38013

Appears in sequences

• Odd composite n such that phi(n) * sigma(n) is one less than a square.at n=20A015722
• a(0) = 1; a(n) = Sum_{1 <= k <= n and k|n} a(n-k).at n=23A067951
• Number of nonnegative solutions to x^2 + y^2 + z^2 < n^2.at n=41A218711
• Composite numbers k such that phi(k) * psi(k) + 1 is a perfect square, where phi is the Euler totient function (A000010) and psi is the Dedekind psi function (A001615).at n=40A309653
• Number of connected n-regular loopless multigraphs on six unlabeled nodes.at n=15A324218