56255domain: NAppears in sequencesa(n) = Sum_{k=0..n} T(n, k)*T(n, n+k), T given by A027960.at n=10A027984Number of nX2 0..1 arrays with every element unequal to 0, 2, 3 or 4 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.at n=13A318039