A384724 a(n) is the number of 4 element sets of distinct integer sided strict rectangles that fill an n X n square.

0, 0, 0, 0, 5, 15, 39, 70, 132, 197, 311, 421, 606, 771, 1047, 1275, 1655, 1968, 2466, 2863, 3510, 4004, 4802, 5416, 6384, 7116, 8286, 9144, 10517, 11535, 13125, 14290, 16140, 17465, 19565, 21085, 23454, 25155, 27837, 29727, 32711, 34836, 38136, 40471, 44142, 46700, 50720, 53548, 57936, 61008

Offset: 1

Author

Janaka Rodrigo, Aug 23 2025

Keywords

• nonn
• new

Comments

A strict rectangle is a rectangle that is not a square.

Examples

			a(5) = 5 sets of integer sided strict rectangles are:
  {(1,2), (1,3), (1,5), (3,5)},
  {(1,2), (1,3), (2,4), (3,4)},
  {(1,2), (1,5), (2,3), (3,4)},
  {(1,2), (1,5), (2,4), (2,5)},
  {(1,3), (1,4), (2,4), (2,5)}.
		

Crossrefs

Cf. A387171.