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 A153769 Numbers n such that 8n-9 is not prime. 1
 0, 1, 3, 6, 8, 9, 12, 13, 15, 16, 18, 19, 21, 23, 24, 27, 28, 30, 32, 33, 36, 37, 38, 39, 41, 42, 43, 44, 45, 48, 50, 51, 52, 53, 54, 57, 58, 60, 63, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 78, 79, 81, 83, 84, 85, 86, 87, 88, 89, 90 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 LINKS Vincenzo Librandi, Table of n, a(n) for n = 1..1000 EXAMPLE Distribution of the terms > a(2) in the following triangular array: *; 3,*; *,*,*; *,*,9,*; *,8,*,*,*; 6,*,*,*,19,*; *,*,*,18,*,*,*; *,*,16,*,*,*,33,*; *,13,*,*,*,32,*,*,*; 9,*,*,*,30,*,*,*,51,*; *,*,*,27,*,*,*,50,*,*,*; *,*,23,*,*,*,48,*,*,*,73,*; *,18,*,*,*,45,*,*,*,72,*,*,*; 12,*,*,*,41,*,*,*,70,*,*,*,99,*; etc. where * marks the non-integer values of (2*h*k + k + h + 5)/4 with h >= k >= 1. - Vincenzo Librandi, Jan 19 2013 MATHEMATICA lst={}; Do[If[!PrimeQ[8*n-9], AppendTo[lst, n]], {n, 0, 500}]; lst (* Vincenzo Librandi, Jul 31 2012 *) Select[Range[0, 100], !PrimeQ[8#-9]&] (* Harvey P. Dale, Jun 08 2015 *) PROG (MAGMA) [n: n in [0..100]| not IsPrime(8*n-9)]; // Vincenzo Librandi, Jul 31 2012 CROSSREFS Cf. A153766. Sequence in context: A084020 A167195 A032489 * A275608 A155723 A095277 Adjacent sequences:  A153766 A153767 A153768 * A153770 A153771 A153772 KEYWORD nonn,easy AUTHOR Vincenzo Librandi, Jan 01 2009 STATUS approved

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Last modified April 8 14:52 EDT 2020. Contains 333314 sequences. (Running on oeis4.)