688205

Appears in sequences

• Number of n X n binary arrays symmetric under 90 degree rotation with all ones connected only in a 1101-0111-0001 pattern in any orientation.at n=16A147237
• Numbers k for which gcd(k, A003961(k)) = gcd(sigma(k), A003961(k)) > 1, and that satisfy Euler's condition for odd perfect numbers (A228058).at n=15A387166