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Search: id:A085582
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| A085582 |
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a(n) = the number of rectangles (orthogonal or not) with corners on an n X n grid of points. |
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+0
4
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| 1, 10, 44, 130, 313, 640, 1192, 2044, 3305, 5078, 7524, 10750, 14993, 20388, 27128, 35448, 45665, 57922, 72636, 89970, 110297, 133976, 161440, 192860, 228857, 269758, 316012, 367974, 426417, 491468, 564120, 644640, 733633, 831674, 939292
(list; graph; listen)
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OFFSET
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2,2
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FORMULA
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a(n)=A000537(n)+A113751(n). - T. D. Noe (noe(AT)sspectra.com), Nov 09 2005
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EXAMPLE
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a(3)=10 because on the 3 X 3 grid there are four 1 X 1 rectangles, two 1 X 2s, two 2 X 1's, one 2 X 2 and one 45-degree rectangle, sqrt(2) X sqrt(2).
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CROSSREFS
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Cf. A000537, A002415.
Cf. A113751 (diagonal rectangles on an n X n grid).
Sequence in context: A057517 A126964 A008532 this_sequence A058310 A005720 A060326
Adjacent sequences: A085579 A085580 A085581 this_sequence A085583 A085584 A085585
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KEYWORD
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nonn
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AUTHOR
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Yuval Dekel (dekelyuval(AT)hotmail.com), Jul 06 2003
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EXTENSIONS
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Edited by Don Reble (djr(AT)nk.ca), Nov 05 2005
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