id:A156876 - OEIS Search Results

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Number of numbers <= n that are safe primes or Sophie Germain primes.

+0
6

0, 1, 2, 2, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 8, 8, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 10, 10, 10, 10, 10, 10, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 12, 12, 12, 12, 12 (list; graph; listen)

	OFFSET	`1,3`
	COMMENT	`a(n) = A156874(n)+A156875(n)-A156877(n) = A000720(n)-A156878(n).`
	LINKS	`R. Zumkeller, Table of n, a(n) for n = 1..10000`
	EXAMPLE	`a(120)=#{2,3,5,7,11,23,29,41,47,53,59,83,89,107,113}=15.`
	CROSSREFS	`A156658, A005384, A005385, A000720.` `Sequence in context: A098388 A157792 A094235 this_sequence A137397 A062571 A102515` `Adjacent sequences: A156873 A156874 A156875 this_sequence A156877 A156878 A156879`
	KEYWORD	`nonn`
	AUTHOR	`Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Feb 18 2009`

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Last modified November 25 08:46 EST 2009. Contains 167481 sequences.

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