251488

Appears in sequences

• Numbers k such that sigma(sigma(k)) == phi(k) (mod sigma(k)).at n=31A067204
• Number of 2Xn 0..3 arrays with no element equal to zero plus the sum of elements to its left or one plus the sum of the elements above it or zero plus the sum of the elements diagonally to its northwest, modulo 4.at n=12A240413
• Number of triangles in a Star of David of size n.at n=29A299965