1824646domain: NAppears in sequencesNumber of positive integers <= 2^n of form x^2 + 13 y^2.at n=24A054227Number 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, 0), (-1, 0, 1), (-1, 1, -1), (1, -1, 0), (1, 1, 0)}.at n=12A149138