

A153083


Numbers such that 2*n + 11 is not prime.


4



2, 5, 7, 8, 11, 12, 14, 17, 19, 20, 22, 23, 26, 27, 29, 32, 33, 35, 37, 38, 40, 41, 42, 44, 47, 50, 52, 53, 54, 55, 56, 57, 59, 61, 62, 65, 66, 67, 68, 71, 72, 74, 75, 77, 79, 80, 82, 83, 86, 87, 88, 89, 92, 95, 96, 97, 98, 99, 101, 102, 103, 104, 105, 107, 110, 112
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OFFSET

1,1


COMMENTS

One less than the associated entry in A155723. [ 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:
*
2,7;
5,12,19;
8,17,26,35;
11,22,33,44,55;
14,27,40,53,66,79;
17,32,47,62,77,92,107;
20,37,54,71,88,105,122,139;
23,42,61,80,99,118,137,156,175;
26,47,68,89,110,131,152,173,194,215;
29,52,75,98,121,144,167,190,213,236,259;
32,57,82,107,132,157,182,207,232,257,282,307;
where * marks the decimal values of (2*h*k + k + h  5) with h >= k >= 1.  Vincenzo Librandi, Jan 16 2013


MATHEMATICA

Select[Range[100], !PrimeQ[2#+11]&] (* Harvey P. Dale, Jul 18 2011 *)


PROG

(MAGMA) [n: n in [1..120]  not IsPrime(2*n + 11)]; // Vincenzo Librandi, Nov 21 2012


CROSSREFS

Cf. A101448, A155546, A155723, A153053.
Sequence in context: A242401 A050941 A299232 * A140592 A153086 A032784
Adjacent sequences: A153080 A153081 A153082 * A153084 A153085 A153086


KEYWORD

nonn,easy


AUTHOR

Vincenzo Librandi, Dec 18 2008


STATUS

approved



