2763520domain: NAppears in sequencesa(n) = 2^n*(2^n - 1)*(2^n - 2)/6.at n=8A026740Triangle, read by rows, where T(n,k) = C(2^k,n-k) for n>=k>=0.at n=74A136501Number of ways to choose three points in an (n X n)-grid (or geoplane).at n=15A178208Quarter-square tetrahedrals: a(n) = k*(k - 1)*(k - 2)/6, k = A002620(n).at n=32A217482