6351660

Appears in sequences

• a(n) = ((prime(n))^4-(prime(n))^2)/4.at n=19A138420
• Triangle read by rows: T(n,k) is the number of endofunctions on [n] whose second-smallest component has size exactly k; n >= 0, 0 <= k <= max(0,n-1).at n=41A350079