1277701domain: NAppears in sequencesNumber of (n+1)X(2+1) 0..1 arrays with the sum of each 2X2 subblock two extreme terms minus its two median terms lexicographically nondecreasing rowwise and columnwise.at n=9A235550Expansion of x^6*(1 + x^3)/(1 - 4*x + 5*x^2 - x^3 - 2*x^4 + x^6 + x^7 - 2*x^8 + x^9).at n=20A290989