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A128422
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Projective plane crossing number of K_{4,n}.
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5
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0, 0, 0, 2, 4, 6, 10, 14, 18, 24, 30, 36, 44, 52, 60, 70, 80, 90, 102, 114, 126, 140, 154, 168, 184, 200, 216, 234, 252, 270, 290, 310, 330, 352, 374, 396, 420, 444, 468, 494, 520, 546, 574, 602, 630, 660, 690, 720, 752, 784, 816, 850, 884, 918, 954, 990, 1026
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,4
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COMMENTS
| Also, a(n) = floor((n - 1)(n - 2) / 3) for n >= 1.
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LINKS
| Eric Weisstein's World of Mathematics, Projective Plane Crossing Number
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FORMULA
| Floor[n/3](2n-3(1+Floor[n/3]))
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MATHEMATICA
| Table[Floor[((n-2)^2+(n-2))/3], {n, 1, 100}] (* From Vladimir Joseph Stephan Orlovsky, Jan 31 2012 *)
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CROSSREFS
| Sequence in context: A100143 A059254 A024518 * A098380 A007782 A035501
Adjacent sequences: A128419 A128420 A128421 * A128423 A128424 A128425
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KEYWORD
| nonn
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AUTHOR
| Eric Weisstein (eric(AT)weisstein.com), Mar 02, 2007
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EXTENSIONS
| Comment added by Christopher Hunt Gribble (chris.eveswell(AT)virgin.net), Oct 13 2009
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