189413

Appears in sequences

• Number of ways to place zero or more nonadjacent 1,1 2,1 3,1 4,0 4,1 5,2 6,3 7,4 polyhexes in any orientation on a planar nXnXn triangular grid.at n=9A155391
• Number of bicolored trees on n unlabeled nodes such that black nodes are not adjacent to each other and every white node is adjacent to a black node.at n=15A339837