7912969

Appears in sequences

• Number of n X 6 0..1 arrays avoiding 0 0 0 and 0 1 0 horizontally and 0 0 1 and 1 1 0 vertically.at n=13A207701
• Numbers k such that concat(k, sigma(k)) and concat(sigma(k), k) are both prime.at n=20A284642