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A156878
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Number of numbers <= n that are neither safe primes and nor Sophie Germain primes.
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5
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 8, 8, 8, 8, 9, 9, 10, 10, 10, 10, 10, 10, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,17
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COMMENTS
| a(n) = A000720(n) - A156876(n).
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LINKS
| R. Zumkeller, Table of n, a(n) for n = 1..10000
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EXAMPLE
| a(120)=#{13,17,19,31,37,43,61,67,71,73,79,97,10,103,109}=15.
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CROSSREFS
| A059500, A005384, A005385.
Sequence in context: A157639 A010096 A063510 * A140474 A091195 A072375
Adjacent sequences: A156875 A156876 A156877 * A156879 A156880 A156881
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KEYWORD
| nonn
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AUTHOR
| Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Feb 18 2009
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