171484domain: NAppears in sequencesNumber of 4 X n 0..2 arrays with horizontal differences mod 3 never 1, vertical differences mod 3 never -1, and rows and columns lexicographically nondecreasing.at n=28A229447Expansion of Product_{i>=2, j>=2} (1 + x^(i*j))^j.at n=45A326831