1070599167domain: NAppears in sequencesa(n) = (4*n^2 - 1)^3.at n=15A069076Number of n-tuples where each entry is chosen from the subsets of {1,2,3} such that the intersection of all n entries is empty.at n=9A128831a(n) = Product_{i=0..2} (2^floor((n+i)/3)-1).at n=30A274626