

A153044


Numbers n such that 2*n9 is not a prime.


3



5, 9, 12, 15, 17, 18, 21, 22, 24, 27, 29, 30, 32, 33, 36, 37, 39, 42, 43, 45, 47, 48, 50, 51, 52, 54, 57, 60, 62, 63, 64, 65, 66, 67, 69, 71, 72, 75, 76, 77, 78, 81, 82, 84, 85, 87, 89, 90, 92, 93, 96, 97, 98, 99, 102, 105, 106, 107, 108, 109, 111, 112, 113, 114, 115, 117, 120
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OFFSET

1,1


COMMENTS

One more than the associated entry in A153039.  R. J. Mathar, Jan 05 2011
The terms after a(1) are the values of 2*h*k + k + h + 5, where h and k are positive integers.  Vincenzo Librandi, Jan 19 2013


LINKS

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


MATHEMATICA

Select[Range[150], !PrimeQ[2#9]&] (* Harvey P. Dale, Mar 05 2011 *)


PROG

(MAGMA) [n: n in [5..121]  not IsPrime(2*n9)]; // Bruno Berselli, Mar 05 2011


CROSSREFS

Cf. A097069, A153039.
Sequence in context: A314612 A314613 A102183 * A106635 A314614 A182617
Adjacent sequences: A153041 A153042 A153043 * A153045 A153046 A153047


KEYWORD

nonn,easy


AUTHOR

Vincenzo Librandi, Dec 17 2008


EXTENSIONS

Corrected and extended by N. J. A. Sloane, May 29 2010


STATUS

approved



