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 A272902 Numbers n such that 6n - 5 is not prime. 0
 1, 5, 9, 10, 15, 16, 20, 21, 23, 25, 29, 30, 32, 35, 37, 40, 42, 43, 44, 45, 49, 50, 51, 54, 55, 58, 60, 61, 65, 66, 68, 70, 72, 75, 76, 79, 80, 81, 83, 85, 86, 87, 89, 90, 93, 94, 95, 98, 99 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS FORMULA a(n) ~ n. - Charles R Greathouse IV, May 09 2016 EXAMPLE a(2) = 5 because 6 * 5 - 5 = 25 that is composite. MATHEMATICA Select[Range[100], Not[PrimeQ[6# - 5]] &] (* Alonso del Arte, May 09 2016 *) PROG (PARI) is(n)=!isprime(6*n-5) \\ Charles R Greathouse IV, May 09 2016 CROSSREFS Sequence in context: A140509 A314580 A314581 * A235033 A327593 A282757 Adjacent sequences:  A272899 A272900 A272901 * A272903 A272904 A272905 KEYWORD nonn,easy AUTHOR Carlos Valencia Alonso, May 09 2016 STATUS approved

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Last modified August 4 20:28 EDT 2021. Contains 346455 sequences. (Running on oeis4.)