652024domain: NAppears in sequencesa(n) = 1681*n^2 - 984*n - 696.at n=19A118060Number of n X 2 -2..2 arrays of 2 X 2 subblock diagonal sums minus antidiagonal sums for some (n+1) X 3 binary array with rows and columns of the latter in lexicographically nondecreasing order.at n=18A227056