id:A057859 - OEIS Search Results

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Number of residue classes modulo n which contain a prime.

+0
3

1, 2, 3, 3, 5, 4, 7, 5, 7, 6, 11, 6, 13, 8, 10, 9, 17, 8, 19, 10, 14, 12, 23, 10, 21, 14, 19, 14, 29, 11, 31, 17, 22, 18, 26, 14, 37, 20, 26, 18, 41, 15, 43, 22, 26, 24, 47, 18, 43, 22, 34, 26, 53, 20, 42, 26, 38, 30, 59, 19, 61, 32, 38, 33, 50, 23, 67, 34, 46 (list; graph; listen)

	OFFSET	`1,2`
	COMMENT	`a(n)=n iff n is prime; a(2n)<=n+1; a(4p)=2*p for primes p>2: a(A001749(n))=A057860(A001749(n)). - Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Jan 11 2004`
	FORMULA	`a(n) = A000010(n)+A001221(n) = n - A057860(n)`
	EXAMPLE	`a(30) = 11 since 30k+m can be prime if m = 2, 3 or 5 (once each with k = 0) or m = 1, 7, 11, 13, 17, 19, 23 or 29 (each for an infinite number of values of k)`
	CROSSREFS	`Cf. A057857.` `Adjacent sequences: A057856 A057857 A057858 this_sequence A057860 A057861 A057862` `Sequence in context: A064920 A064916 A062854 this_sequence A029579 A106647 A130157`
	KEYWORD	`nonn`
	AUTHOR	`Henry Bottomley (se16(AT)btinternet.com), Sep 08 2000`

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Last modified October 12 15:26 EDT 2008. Contains 144830 sequences.

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