108306280domain: NAppears in sequencesNumber of n X n symmetric matrices with (0,1) entries and all row sums 2.at n=11A000986Number of n X n symmetric binary matrices with all row sums 9.at n=2A139676Number of 11 X 11 arrays of squares of integers, symmetric about main diagonal, with all rows summing to n.at n=2A156405