158280

Appears in sequences

• Irregular table read by rows: Take a diagonal-edged (or diamond-shaped) checkerboard with all diagonals drawn, as in A333434. Then T(n,k) = number of k-sided polygons in that figure for k >= 3.at n=45A333458
• a(n) is the number of isosceles trapezoids in a triangular grid of side length n.at n=29A389363