308101domain: NPropertiesPrimalityPrimeyesAppears in sequencesNumber of ways to place zero or more nonadjacent 1,0 1,1 2,1 3,2 3,3 4,2 5,2 5,3 polyhexes in any orientation on a planar n X n X n triangular grid.at n=9A155410Prime numbersat n=26652