

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
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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 noninteger 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



