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 A167021 a(n) = 1 iff 6n+1 is prime. 4
 1, 1, 1, 0, 1, 1, 1, 0, 0, 1, 1, 1, 1, 0, 0, 1, 1, 1, 0, 0, 1, 0, 1, 0, 1, 1, 1, 0, 0, 1, 0, 1, 1, 0, 1, 0, 1, 1, 0, 1, 0, 0, 0, 0, 1, 1, 1, 0, 0, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1, 1, 1, 0, 0, 1, 0, 1, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 0, 1, 1, 0, 0, 0, 1, 1, 1, 1, 0, 1 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Table of n, a(n) for n=1..105. Index entries for characteristic functions EXAMPLE a(3) = 1 because 6*3+1 is prime; a(4) = 0 since 6*4+1 is composite. MATHEMATICA If[PrimeQ[6#+1], 1, 0]&/@Range[120] (* Harvey P. Dale, Apr 03 2012 *) PROG (PARI) a(n) = isprime(6*n+1); \\ Michel Marcus, Jan 19 2019 (Magma) [IsPrime(6*n+1) select 1 else 0:n in [1..105]]; // Marius A. Burtea, Oct 06 2019 CROSSREFS Cf. A024899, A167020, A132350. For n < 14, a(n) = A132350(n). Sequence in context: A219009 A353519 A267708 * A267687 A304653 A132350 Adjacent sequences: A167018 A167019 A167020 * A167022 A167023 A167024 KEYWORD nonn AUTHOR Washington Bomfim, Oct 27 2009 STATUS approved

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Last modified June 25 07:38 EDT 2024. Contains 373697 sequences. (Running on oeis4.)