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A156878 Number of numbers <= n that are neither safe primes and nor Sophie Germain primes. 5
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; text; internal format)
OFFSET

1,17

COMMENTS

a(n) = A000720(n) - A156876(n).

LINKS

R. Zumkeller, Table of n, a(n) for n = 1..10000

EXAMPLE

a(120)=#{13,17,19,31,37,43,61,67,71,73,79,97,10,103,109}=15.

CROSSREFS

A059500, A005384, A005385.

Sequence in context: A010096 A230864 A063510 * A214454 A140474 A091195

Adjacent sequences:  A156875 A156876 A156877 * A156879 A156880 A156881

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller, Feb 18 2009

STATUS

approved

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Last modified May 23 02:46 EDT 2017. Contains 286909 sequences.