5018010431domain: NAppears in sequencesNumber of n X n 0..4 matrices whose square is also a 0..4 matrix.at n=4A213986T(n,k)=Number of n X n 0..k matrices whose square is also a 0..k matrix.at n=32A213990Number of 5X5 0..n matrices whose square is also a 0..n matrix.at n=3A213994