A153245 Numbers n>1 such that 6*n-7 is not prime.

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

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. A046953, A153134, A153135.

Sequence in context: A173417 A031021 A353444 * 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