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 A167020 a(n) = 1 iff 6n-1 is prime. 6
 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 0, 1, 0, 1, 1, 0, 1, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1, 1, 1, 0, 1, 1, 0, 0, 0, 0, 1, 1, 1, 0, 1, 1, 1, 1, 0, 1, 0, 1, 0, 0, 1, 1, 0, 0, 0, 0, 1, 1, 1, 0, 0, 0, 1, 1, 0, 1, 0, 0, 1, 0, 1, 0, 1, 1, 0, 1, 1, 0, 1, 0, 1, 0, 1, 1, 0, 1, 0, 0, 0, 0, 0, 1, 1, 1, 0, 0, 1, 1, 1, 0, 0, 1, 0, 0 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Vincenzo Librandi, Table of n, a(n) for n = 1..5000 Index entries for characteristic functions EXAMPLE a(5) = 1 because 6*5-1 is prime, a(6) = 0 since 6*6-1 is composite. MATHEMATICA Table[If[PrimeQ[6 n - 1], 1, 0], {n, 100}] (* Vincenzo Librandi, Jan 19 2019 *) 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..100]]; // Vincenzo Librandi, Jan 19 2019 CROSSREFS Cf. A024898, A167021. Sequence in context: A351564 A237048 A344880 * A236862 A163812 A163818 Adjacent sequences: A167017 A167018 A167019 * A167021 A167022 A167023 KEYWORD nonn AUTHOR Washington Bomfim, Oct 27 2009 STATUS approved

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Last modified May 27 03:56 EDT 2024. Contains 372847 sequences. (Running on oeis4.)