221027

Appears in sequences

• Composite numbers k such that if k = a U b (where U denotes concatenation) then a' + b' = k', where a', b' and k' are the arithmetic derivatives of a, b and k.at n=29A239724
• Number of (n+2)X(7+2) 0..1 arrays with every 3X3 subblock diagonal sum plus antidiagonal sum nondecreasing horizontally, vertically and ne-to-sw antidiagonally.at n=19A253840