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 A228373 Numbers n such that 27*n + 1 is not prime. 1
 0, 1, 2, 3, 5, 7, 8, 9, 11, 12, 13, 15, 17, 19, 21, 22, 23, 24, 25, 26, 27, 29, 31, 32, 33, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 49, 50, 51, 52, 53, 55, 56, 57, 59, 61, 62, 63, 64, 65, 67, 68, 69, 70, 71, 72, 73, 75, 77, 78, 79, 81, 82, 83, 85, 86, 87, 89, 90 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS Complement of A224467. LINKS Vincenzo Librandi, Table of n, a(n) for n = 1..1000 MATHEMATICA Select[Range[0, 120], ! PrimeQ[27 # + 1]&] PROG (MAGMA) [n: n in [0..120] | not IsPrime(27*n + 1)]; CROSSREFS Cf. A224467. Sequence in context: A053661 A171944 A134623 * A156271 A186513 A246438 Adjacent sequences:  A228370 A228371 A228372 * A228374 A228375 A228376 KEYWORD nonn,less,easy AUTHOR Vincenzo Librandi, Aug 21 2013 STATUS approved

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Last modified September 23 08:23 EDT 2021. Contains 347610 sequences. (Running on oeis4.)