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A071841 Number of primes == 5 mod 8 <= n. 0
0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7, 7 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,13

LINKS

Table of n, a(n) for n=1..105.

MATHEMATICA

Accumulate[Table[If[PrimeQ[n]&&Mod[n, 8]==5, 1, 0], {n, 110}]] (* Harvey P. Dale, Apr 28 2018 *)

PROG

(PARI) for(n=1, 200, print1(sum(i=1, n, if((i*isprime(i)-5)%8, 0, 1)), ", "))

CROSSREFS

Sequence in context: A097430 A054900 A046042 * A097876 A177830 A111859

Adjacent sequences:  A071838 A071839 A071840 * A071842 A071843 A071844

KEYWORD

easy,nonn

AUTHOR

Benoit Cloitre, Jun 08 2002

STATUS

approved

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Last modified October 14 03:58 EDT 2019. Contains 327995 sequences. (Running on oeis4.)