336798domain: NAppears in sequencesExpansion of 1/(1-3*x)^6; 6-fold convolution of A000244 (powers of 3).at n=6A036219a(n) = (0^n + 3^n*binomial(2*n,n))/2.at n=6A098401Number of n X 2 0..2 arrays with some element plus some horizontally or vertically adjacent neighbor totalling two no more than once.at n=8A268622