22815114domain: NAppears in sequencesNumber of 13X2 integer matrices with each row summing to zero, row elements in nondecreasing order, rows in lexicographically nondecreasing order, and the sum of squares of the elements <= 2*n^2 (number of collections of 13 zero-sum 2-vectors with total modulus squared not more than 2*n^2, ignoring vector and component permutations).at n=28A192714