id:A018809 - OEIS Search Results

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Number of lines through exactly 2 points of an n X n grid of points.

+0
3

0, 0, 6, 12, 48, 108, 248, 428, 764, 1196, 1900, 2668, 3824, 5244, 7248, 9380, 12192, 15372, 19528, 24020, 29732, 36052, 43808, 51836, 61636, 72492, 85308, 98492, 114012, 130668, 150196, 170828, 194768, 220276, 249452, 279284, 312572, 348036 (list; graph; listen)

	OFFSET	`0,3`
	FORMULA	`1/2 (f(n, 4) - 2 f(n, 3) + f(n, 2)) where f(n, k) = Sum ((n - \|x\|)(n - \|y\|)); -n<x<n, -n<y<n, (x, y)=k.`
	CROSSREFS	`Sequence in context: A052904 A106692 A032470 this_sequence A117866 A094060 A076722` `Adjacent sequences: A018806 A018807 A018808 this_sequence A018810 A018811 A018812`
	KEYWORD	`nonn`
	AUTHOR	`David W. Wilson (davidwwilson(AT)comcast.net)`

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Last modified December 2 15:58 EST 2008. Contains 150992 sequences.

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