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Search: id:A030117
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| A030117 |
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Number of triangles a queen can make (starting anywhere) on an n X n board. |
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+0
1
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| 0, 0, 4, 28, 80, 180, 332, 560, 864, 1272, 1780, 2420, 3184, 4108, 5180, 6440, 7872, 9520, 11364, 13452, 15760, 18340, 21164, 24288, 27680, 31400, 35412, 39780, 44464, 49532, 54940, 60760, 66944, 73568, 80580, 88060, 95952, 104340, 113164
(list; graph; listen)
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OFFSET
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0,3
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LINKS
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Problem of the week, Web site - problem 855
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FORMULA
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Harris Kwong (kwong(AT)cs.fredonia.edu): 13 Binomial[ n, 3 ] + 5 Binomial[ n, 2 ] if n is odd or 13 Binomial[ n, 3 ] + 5 Binomial[ n, 2 ] - n/2 if n is even.
G.f.: 4*x^2 * (2*x^3 + 5*x^2 + 5*x + 1)/((x - 1)^3*(x + 1))
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CROSSREFS
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Sequence in context: A101002 A085024 A085001 this_sequence A005634 A077595 A092712
Adjacent sequences: A030114 A030115 A030116 this_sequence A030118 A030119 A030120
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KEYWORD
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nonn,easy
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AUTHOR
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njas
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EXTENSIONS
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More terms from Erich Friedman (erich.friedman(AT)stetson.edu).
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