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 A101787 a(n) = |S(n)| where S(n) = {i : 1 <= i <= n and 4*i-1 and 8*i-1 are primes}. 1
 1, 1, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 6, 6, 6, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 8, 8, 8, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 10, 10, 10, 10, 10 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS Number of Lucasian primes that do not exceed 4*n-1. [Corrected by Amiram Eldar, May 23 2024] LINKS Table of n, a(n) for n=1..94. MATHEMATICA Accumulate[Table[Boole[And @@ PrimeQ[{4, 8}*i - 1]], {i, 1, 100}]] (* Amiram Eldar, May 23 2024 *) CROSSREFS Cf. A002515, A101788. Sequence in context: A156752 A345073 A086673 * A343607 A269024 A244160 Adjacent sequences: A101784 A101785 A101786 * A101788 A101789 A101790 KEYWORD easy,nonn AUTHOR Douglas Stones (dssto1(AT)student.monash.edu.au), Dec 16 2004 EXTENSIONS Name corrected by Amiram Eldar, May 23 2024 STATUS approved

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Last modified June 18 03:29 EDT 2024. Contains 373468 sequences. (Running on oeis4.)