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A153351 Numbers n such that 7*n+2 is not prime. 2
1, 2, 4, 6, 7, 8, 9, 10, 12, 13, 14, 16, 17, 18, 19, 20, 22, 24, 25, 26, 28, 29, 30, 31, 32, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 46, 48, 49, 50, 52, 54, 55, 56, 58, 59, 60, 61, 62, 64, 66, 67, 68, 69, 70, 72, 73, 74, 75, 76, 78, 79, 80, 82, 83, 84, 85, 86, 87, 88, 89, 90 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

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

EXAMPLE

Distribution of the odd terms in the following triangular array:

1;

*,*;

*,*,*;

*,*,*,*;

*,*,*,*,17;

*,9,*,*,*,*;

*,*,*,19,*,*,*;

7,*,*,*,*,*,*,41;

*,*,*,*,*,35,*,*,*;

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

*,*,*,*,*,*,49,*,*,*,*;

*,*,*,*,39,*,*,*,*,*,*,89;

*,19,*,*,*,*,*,*,73,*,*,*,*; etc.

where * marks the non-integer values of (4*h*k + 2*k + 2*h - 1)/7 with h >= k >= 1. - Vincenzo Librandi, Jan 17 2013

MATHEMATICA

Select[Range[200], !PrimeQ[7 # + 2] &] (* Vincenzo Librandi, Jan 13 2013 *)

PROG

(MAGMA) [n: n in [0..150] | not IsPrime(7*n + 2)]; // Vincenzo Librandi, Jan 13 2013

CROSSREFS

Cf. A105772.

Sequence in context: A147613 A155939 A114145 * A153343 A136499 A047513

Adjacent sequences:  A153348 A153349 A153350 * A153352 A153353 A153354

KEYWORD

nonn,easy

AUTHOR

Vincenzo Librandi, Dec 24 2008

EXTENSIONS

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

STATUS

approved

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Last modified October 21 14:16 EDT 2019. Contains 328301 sequences. (Running on oeis4.)