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A347751
Number of finite edges in the graph formed when every pair of vertices of a row of n adjacent congruent rectangles are joined by an infinite line.
2
0, 8, 36, 124, 300, 664, 1200, 2108, 3388, 5232, 7568, 10852, 14892, 20288, 26704, 34540, 43812, 55400, 68584, 84684, 103004, 124216, 147888, 175820, 206788, 242424, 281560, 325708, 374148, 429416, 489000, 556412, 629804, 710536, 797280, 892564, 994588, 1107744, 1228432, 1359292, 1498788
OFFSET
0,2
COMMENTS
See A344993 and A347750 for images of the rectangles.
FORMULA
a(n) = A344993(n) + A347750(n) - 1.
EXAMPLE
a(1) = 8 as connecting the four vertices of a single rectangle forms four new edges inside the rectangle, giving a total of 4 + 4 = 8 total edges.
a(2) = 36 as connecting the six vertices of two adjacent rectangles forms twenty-two edges inside the rectangles while also forming eight edges outside the rectangles. The total number of edges is then 6 + 22 + 8 = 36.
CROSSREFS
Cf. A344993 (number of polygons), A347750 (number of intersections), A331757 (number of edges on or inside the rectangles).
Sequence in context: A290892 A144901 A054470 * A341222 A213581 A276279
KEYWORD
nonn
AUTHOR
STATUS
approved