121316domain: NAppears in sequencesNumber of nondecreasing arrangements of n+2 numbers in 0..6 with each number being the sum mod 7 of two others.at n=15A183909Number of (n+2)X(1+2) 0..3 arrays with every 3X3 subblock row and column sum not 1 3 6 or 8 and every diagonal and antidiagonal sum 1 3 6 or 8.at n=12A252046