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A153184 Numbers n such that 3*n-2 is not prime. 4
1, 2, 4, 6, 8, 9, 10, 12, 14, 16, 17, 18, 19, 20, 22, 24, 26, 28, 29, 30, 31, 32, 34, 36, 38, 39, 40, 41, 42, 44, 45, 46, 48, 49, 50, 52, 54, 56, 57, 58, 59, 60, 62, 63, 64, 66, 68, 69, 70, 72, 73, 74, 76, 78, 79, 80, 82, 83, 84, 85, 86, 87, 88, 89, 90, 92, 94, 96, 97, 98, 99, 100 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

One more than the associated value in A153309. - R. J. Mathar, Jan 05 2011

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

FORMULA

a(n) ~ n. - Charles R Greathouse IV, Oct 26 2015

EXAMPLE

Distribution of the odd terms > a(1) in the following triangular array:

*;

*,9;

*,*,17;

*,*,*,*;

*,19,*,*,41;

*,*,31,*,*,57;

*,*,*,*,*,*,*;

*,29,*,*,63,*,*,97;

*,*,45,*,*,83,*,*,121;

*,*, *,*,*,*, *,*, *, *;

*,39,*,*,85,*,*,131,*,*,177;

*,*,59,*,*,109,*,*,159,*,*,209; etc.

where * marks the non-integer values of (4*h*k + 2*k + 2*h + 3)/3 with h >= k >= 1. - Vincenzo Librandi, Jan 17 2013

MATHEMATICA

lst={}; Do[If[ !PrimeQ[3*n-2], AppendTo[lst, n]], {n, 5!}]; lst (* Vladimir Joseph Stephan Orlovsky, Dec 22 2008 *)

Select[Range[0, 100], !PrimeQ[3 # - 2] &] (* Vincenzo Librandi, Jan 12 2013 *)

PROG

(MAGMA) [n: n in [0..120] | not IsPrime(3*n - 2)]; // Vincenzo Librandi, Jan 12 2013

(PARI) is(n)=!isprime(3*n-2) \\ Charles R Greathouse IV, Oct 26 2015

CROSSREFS

Cf. A153183, A088878.

Sequence in context: A285517 A003254 A247875 * A047412 A282760 A296214

Adjacent sequences:  A153181 A153182 A153183 * A153185 A153186 A153187

KEYWORD

nonn,easy

AUTHOR

Vincenzo Librandi, Dec 20 2008

EXTENSIONS

Erroneous comment deleted by N. J. A. Sloane, Jun 23 2010

STATUS

approved

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Last modified March 20 09:50 EDT 2019. Contains 321345 sequences. (Running on oeis4.)