id:A116921 - OEIS Search Results

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a(n) = largest integer <= n/2 which is coprime to n.

+0
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0, 1, 1, 1, 2, 1, 3, 3, 4, 3, 5, 5, 6, 5, 7, 7, 8, 7, 9, 9, 10, 9, 11, 11, 12, 11, 13, 13, 14, 13, 15, 15, 16, 15, 17, 17, 18, 17, 19, 19, 20, 19, 21, 21, 22, 21, 23, 23, 24, 23, 25, 25, 26, 25, 27, 27, 28, 27, 29, 29, 30, 29, 31, 31, 32, 31, 33, 33, 34, 33, 35, 35, 36, 35, 37, 37 (list; graph; listen)

	OFFSET	`1,5`
	COMMENT	`A116921(n) + A116922(n) = n. For n>= 3, A116922(n) - A116921(n) is 1 if n is odd, is 2 if n is a multiple of 4, and is 4 if n is congruent to 2 (mod 4).`
	FORMULA	`For n >= 3, a(n) = (n-1)/2 if n is odd, a(n) = n/2 - 1 if n is a multiple of 4, and a(n) = n/2 - 2 if n is congruent to 2 (mod 4).`
	CROSSREFS	`Cf. A116922.` `Sequence in context: A057938 A048619 A116087 this_sequence A093068 A097357 A123621` `Adjacent sequences: A116918 A116919 A116920 this_sequence A116922 A116923 A116924`
	KEYWORD	`easy,nonn`
	AUTHOR	`Leroy Quet (qq-quet(AT)mindspring.com), Feb 26 2006`
	EXTENSIONS	`More terms from Wyatt Lloyd (wal118(AT)psu.edu), Mar 25 2006`

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

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