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Search: id:A117717
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| A117717 |
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Maximal number of regions obtained by a straight line drawing of the complete bipartite graph K_{n,n}. |
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+0
1
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| 0, 2, 13, 45, 116, 250, 477, 833, 1360, 2106, 3125, 4477, 6228, 8450, 11221, 14625, 18752, 23698, 29565, 36461, 44500, 53802, 64493, 76705, 90576, 106250, 123877, 143613
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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This sequence is in the same spirit as A000127 where a formula is given for the maximal number of regions obtained by a straight line drawing of the complete graph K_n with the vertices located on the perimeter of a circle. This yields the often quoted sequence 1,2,4,8,16,31,...
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FORMULA
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a(n) = n^2 - 2n + C(n,2)^2 + 1
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MAPLE
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n^2-2*n+(numbcomb(n, 2))^2+1
a:=n->sum((n+j^3), j=1..n): seq(a(n), n=0..27); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Jul 27 2006
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CROSSREFS
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Cf. A000127.
Sequence in context: A025194 A084156 A002534 this_sequence A005584 A072416 A056305
Adjacent sequences: A117714 A117715 A117716 this_sequence A117718 A117719 A117720
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KEYWORD
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nonn
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AUTHOR
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Patricia A. Carey and Anant P. Godbole (petrepterodactyl(AT)gmail.com), Apr 13 2006
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