129286

Appears in sequences

• Triangular numbers whose sum of squared digits is also triangular.at n=31A094890
• Number of deco polyominoes of area n. A deco polyomino is a directed column-convex polyomino in which the height, measured along the diagonal, is attained only in the last column.at n=13A121691
• a(n) = t(n)_t(n) where t() = triangular numbers A000217.at n=21A122628
• Numbers n with the property that the symmetric representation of sigma(n) has four parts, each of width one and two regions meet at the center of the Dyck path.at n=28A264104