1767052domain: NAppears in sequencesIndices of 9-gonal numbers which are also heptagonal.at n=3A048919Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, 1), (0, 1, -1), (1, 0, 1), (1, 1, -1)}.at n=13A148721