205775541009domain: NAppears in sequencesNumber of (n+1)X(2+1) 0..3 arrays x(i,j) with every row sum{j*x(i,j), j=1..2+1} equal, and every column sum{i*x(i,j), i=1..n+1} equal, with top left element <= 1.at n=18A232524