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A153245 Numbers n>1 such that 6*n-7 is not prime. 4
7, 12, 14, 17, 21, 22, 25, 27, 28, 32, 35, 36, 37, 38, 42, 47, 49, 51, 52, 55, 56, 57, 58, 62, 63, 64, 67, 69, 70, 72, 74, 77, 80, 82, 84, 87, 89, 90, 91, 92, 93, 97, 98, 102, 103, 105, 106, 107, 112, 113, 116, 117, 119, 120, 122, 123, 124, 126, 127, 129, 131, 132, 133 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

One more than the associated value in A046953. - R. J. Mathar, Jan 05 2011

LINKS

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

EXAMPLE

Distribution of the terms in the following triangular array:

*;

*,*;

*,7,*;

*,*,*,*;

*,*,14,*,*;

*,12,*,*,25,*;

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

*,*,21,*,*,38,*,*;

*,17,*,*,36,*,*,55,*;

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

*,*,28,*,*,51,*,*,74,*,*;

*,22,*,*,47,*,*,72,*,*,97,*; etc.

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

MATHEMATICA

Select[Range[2, 200], !PrimeQ[6 # - 7] &] (* Vincenzo Librandi, Jan 12 2013 *)

PROG

(MAGMA) [n: n in [2..150] | not IsPrime(6*n - 7)]; // Vincenzo Librandi, Jan 12 2013

CROSSREFS

Cf. A153134, A153135.

Sequence in context: A078835 A173417 A031021 * A317670 A062730 A287562

Adjacent sequences:  A153242 A153243 A153244 * A153246 A153247 A153248

KEYWORD

nonn,easy

AUTHOR

Vincenzo Librandi, Dec 21 2008

EXTENSIONS

More terms from Vladimir Joseph Stephan Orlovsky, Dec 23 2008

STATUS

approved

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Last modified August 15 15:17 EDT 2020. Contains 336504 sequences. (Running on oeis4.)