680922domain: NAppears in sequencesLet M = {{0, 1}, {1/3, 2}}; w[1] = {0, 1}; w[n] = M.w[n - 1]; then a(n) = w[n][[1]]*3^Floor[2*(n - 1)/3].at n=10A116951Number of nX3 0..3 arrays with every row and column nondecreasing rightwards and downwards, and the number of instances of each value within one of each other.at n=25A201446