145131

Appears in sequences

• Let [n] = {1,2,...,n}. Let G_n be the union of all closed line segments joining any two elements of [n] X [n] along a vertical or horizontal line, or along a line with slope +-1. Then a(n) = combined total of the number of (nondegenerate) triangles and rectangles for which all edges are subsets of G_n.at n=19A098921
• Total size of all principal order ideals in the poset of integer partitions of n with the refinement order.at n=21A265947