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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.)