300113domain: NAppears in sequencesNumbers k such that replacing each nonzero digit d with the d-th prime (replacing each 0 digit with a 1) yields a square.at n=26A048383Number of (n+1) X (n+1) -8..8 symmetric matrices with every 2 X 2 subblock having sum zero and one or two distinct values.at n=21A211466