id:A111143 - OEIS Search Results

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Number of different ways of drawing chords in a circle of numbers from 1 to n such that the sums of the numbers on the two sides of the chord are equal.

+0
1

1, 0, 0, 1, 1, 0, 0, 2, 1, 0, 0, 1, 2, 2, 0, 1, 1, 0, 0, 2, 1, 0, 1, 1, 2, 0, 0, 1, 1, 0, 2, 2, 1, 0, 0, 1, 2, 1, 0, 1, 1, 0, 0, 2, 1, 0, 1, 1, 3, 0, 0, 1, 2, 1, 1, 2, 1, 0, 0, 1, 2, 4, 3, 2, 1, 0, 0, 3, 1, 0, 0, 1, 2, 0, 0, 2, 1, 0, 3, 2, 1, 0, 0, 1, 2, 1, 0, 1, 4, 0, 0, 2, 1, 4, 0, 1, 3, 0 (list; graph; listen)

	OFFSET	`2,8`
	EXAMPLE	`a(5) = 1 because in a circle with the numbers from 1 to 5 we can put a chord from 1 and 4 and the sum of both sides is the same.` `a(9) = 2 as in a circle with the numbers from 1 to 9 we can put a chord in two ways, one from 2 to 7 and another from 6 to 9.`
	CROSSREFS	`Sequence in context: A014674 A015339 A137867 this_sequence A004197 A048571 A025880` `Adjacent sequences: A111140 A111141 A111142 this_sequence A111144 A111145 A111146`
	KEYWORD	`easy,nonn`
	AUTHOR	`Joao B. Oliveira (oliveira(AT)inf.pucrs.br), Oct 18 2005`

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Last modified August 29 17:54 EDT 2008. Contains 143238 sequences.

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