101619domain: NAppears in sequencesNumber of Greg trees with n black nodes.at n=12A052302Coefficients of Maclaurin series for (1-9x-9x^2)^(-1/3).at n=6A180400Square array T(n,k), n>=0, k>=0, read by antidiagonals downwards, where column k is the expansion of 1/(1 - 9*x*(1 + x)^k)^(1/3).at n=34A361839