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 A153170 Numbers k such that 3*k + 2 is not prime. 8
 2, 4, 6, 8, 10, 11, 12, 14, 16, 18, 20, 21, 22, 24, 25, 26, 28, 30, 31, 32, 34, 36, 38, 39, 40, 41, 42, 44, 46, 47, 48, 50, 51, 52, 53, 54, 56, 58, 60, 61, 62, 64, 66, 67, 68, 69, 70, 71, 72, 73, 74, 76, 78, 80, 81, 82, 84, 86, 88, 90, 91, 92, 94, 95, 96, 98, 99, 100, 101, 102 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Contains the positive even numbers (A005843) and the odd numbers of the form 2*A059324(.) + 1. - R. J. Mathar, Nov 27 2010 Numbers k such that (3*k)!/(3*k + 2) is an integer. - Peter Bala, Jan 25 2017 LINKS Vincenzo Librandi, Table of n, a(n) for n = 1..1000 EXAMPLE Distribution of the odd terms in the following triangular array:   *;   *,   *;   *,  11,   *;   *,   *,   *,   *;   *,   *,  25,   *,   *;   *,  21,   *,   *,  47,   *;   *,   *,   *,   *,   *,   *,   *;   *,   *,  39,   *,   *,  73,   *,   *;   *,  31,   *,   *,  69,   *,   *, 107,   *;   *,   *,   *,   *,   *,   *,   *,   *,   *,   *;   *,   *,  53,   *,   *,  99,   *,   *, 145,   *,   *;   *,  41,   *,   *,  91,   *,   *, 141,   *,   *, 191,   *; etc., where * marks the noninteger values of (4*h*k + 2*k + 2*h - 1)/3 with h >= k >= 1. - Vincenzo Librandi, Jan 15 2013 MAPLE for n from 0 to 100 do if irem(factorial(3*n), 3*n+2) = 0 then print(n); end if; end do: # Peter Bala, Jan 25 2017 MATHEMATICA Select[Range[1, 200], !PrimeQ[3*# + 2] &] (* Vincenzo Librandi, Oct 11 2012 *) PROG (PARI) for(n=1, 200, if(!isprime(3*n+2), print1(n, ", "))) \\  Joerg Arndt, Nov 27 2010 (MAGMA) [n: n in [1..110] | not IsPrime(3*n + 2)]; // Vincenzo Librandi, Oct 11 2012 CROSSREFS Cf. A024893, A014076, A045751, A095277, A153088, A153329, A153343. Sequence in context: A176995 A225793 A154809 * A067030 A072427 A337430 Adjacent sequences:  A153167 A153168 A153169 * A153171 A153172 A153173 KEYWORD nonn,easy AUTHOR Vincenzo Librandi, Dec 20 2008 EXTENSIONS Edited by N. J. A. Sloane, Jun 23 2010 STATUS approved

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Last modified June 18 14:48 EDT 2021. Contains 345114 sequences. (Running on oeis4.)