507571domain: NPropertiesPrimalityPrimeyesAppears in sequencesSmallest m such that (sum of binary digits of m*(m+1)/2) = n.at n=31A211201Number of (n+2)X(1+2) 0..3 arrays with every 3X3 subblock row and diagonal sum equal to 0 1 3 6 or 7 and every 3X3 column and antidiagonal sum not equal to 0 1 3 6 or 7.at n=16A252298Prime numbersat n=42108