1883328

Appears in sequences

• a(n) = sqrt(2)*( (3+2*sqrt(2))^n - (3-2*sqrt(2))^n ).at n=8A081554
• Number of maximal rectangles in all L-convex polyominoes of semiperimeter n. An L-convex polyomino is a convex polyomino where any two cells can be connected by a path internal to the polyomino and which has at most 1 change of direction (i.e., one of the four orientations of the letter L). A maximal rectangle in an L-convex polyomino P is a rectangle included in P that is maximal with respect to inclusion.at n=11A181369
• a(n) = Pell(n) * A004018(n) for n>=1 with a(0)=1, where A004018(n) is the number of ways of writing n as a sum of 2 squares.at n=16A205508
• The number of unilevel points (unique points at their height) on Delannoy paths ending when x = n.at n=16A371596