279219domain: NAppears in sequencesG.f.: Sum_{n>=0} x^(n*(n+1)/2) / Product_{k=1..n} (1 - (n-k+1)*x^k).at n=17A204855Number of nX5 0..1 arrays avoiding 0 0 0 and 0 1 0 horizontally and 0 1 0 and 1 0 1 vertically.at n=5A207855Number of 6Xn 0..1 arrays avoiding 0 0 0 and 0 1 0 horizontally and 0 1 0 and 1 0 1 vertically.at n=4A207861