id:A074990 - OEIS Search Results

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Number of primes between n and 3n.

+0
1

2, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6, 6, 6, 7, 8, 9, 8, 9, 8, 9, 10, 10, 10, 11, 12, 12, 13, 14, 13, 14, 13, 13, 14, 15, 16, 17, 17, 18, 18, 18, 17, 17, 17, 18, 18, 19, 19, 19, 19, 20, 21, 21, 21, 21, 22, 23, 23, 24, 23, 24, 24, 24, 24, 25, 26, 27, 27, 27, 27, 27, 27, 27, 26, 26, 27, 28 (list; graph; listen)

	OFFSET	`1,1`
	COMMENT	`Difference a(n+1)-a(n) = 0,+/-1.`
	EXAMPLE	`a(4) = 3 because between 4 and 12 there are 3 primes: 5, 7, 11; a(7) = 4 because between 7 and 21 there are 4 primes: 11, 13, 17, 19.`
	MATHEMATICA	`s=3; a[n_] := PrimePi[s*n]-PrimePi[n]`
	CROSSREFS	`Sequence in context: A121830 A020911 A029125 this_sequence A102605 A112995 A078452` `Adjacent sequences: A074987 A074988 A074989 this_sequence A074991 A074992 A074993`
	KEYWORD	`nonn`
	AUTHOR	`Zak Seidov (zakseidov(AT)yahoo.com), Oct 02 2002`

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Last modified September 5 19:27 EDT 2008. Contains 143485 sequences.

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