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Search: id:A062890
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| A062890 |
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Number of quadrilaterals that can be formed with perimeter n. In other words, partitions of n into four parts such that the sum of any three is more than the fourth. |
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6
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| 0, 0, 0, 0, 1, 1, 1, 2, 3, 4, 5, 7, 8, 11, 12, 16, 18, 23, 24, 31, 33, 41, 43, 53, 55, 67, 69, 83, 86, 102, 104, 123, 126, 147, 150, 174, 177, 204, 207, 237, 241, 274, 277, 314, 318, 358, 362, 406, 410, 458, 462, 514, 519, 575, 579, 640, 645, 710
(list; graph; listen)
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OFFSET
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0,8
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REFERENCES
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G. E. Andrews, P. Paule and A. Riese, MacMahon's Partition Analysis IX: k-gon partitions, Bull. Austral Math. Soc., 64 (2001), 321-329.
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LINKS
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T. D. Noe, Table of n, a(n) for n=0..1000
G. E. Andrews, P. Paule and A. Riese, MacMahon's partition analysis III. The Omega package, p. 19.
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FORMULA
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G.f.: x^4*(1+x+x^5)/((1-x^2)*(1-x^3)*(1-x^4)*(1-x^6)).
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EXAMPLE
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a(7) = 2 as the two partitions are (1,2,2,2), (1,1,2,3) and in each sum of any three is more than the fourth.
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CROSSREFS
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Cf. A005044, A069906, A069907.
Sequence in context: A054021 A066191 A166159 this_sequence A058586 A090467 A053868
Adjacent sequences: A062887 A062888 A062889 this_sequence A062891 A062892 A062893
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KEYWORD
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nonn,easy
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AUTHOR
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Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Jun 29 2001
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EXTENSIONS
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More terms from Vladeta Jovovic (vladeta(AT)EUnet.yu) and Dean Hickerson (dean.hickerson(AT)yahoo.com), Jul 01 2001
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