

A153043


Numbers n > 1 such that 2*n3 is not a prime.


7



2, 6, 9, 12, 14, 15, 18, 19, 21, 24, 26, 27, 29, 30, 33, 34, 36, 39, 40, 42, 44, 45, 47, 48, 49, 51, 54, 57, 59, 60, 61, 62, 63, 64, 66, 68, 69, 72, 73, 74, 75, 78, 79, 81, 82, 84, 86, 87, 89, 90, 93, 94, 95, 96, 99, 102, 103, 104, 105, 106, 108, 109, 110
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OFFSET

1,1


COMMENTS

One more than the associated value in A104275.  R. J. Mathar, Jan 05 2011
2*A155705(m,n)3 = (2n+1)*(2m+1) are nonprime: all A155705(.,.) are in this sequence.
The terms after a(1) are the values of 2*h*k + k + h + 2, 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[2, 200], !PrimeQ[2*#3]&] (* Vladimir Joseph Stephan Orlovsky, Feb 09 2012 *)


PROG

(MAGMA) [n: n in [2..102]  not IsPrime(2*n3)]; // Bruno Berselli, Mar 05 2011


CROSSREFS

Cf. A098090, A153040, A155705.
Sequence in context: A174682 A287126 A270095 * A171504 A287445 A119720
Adjacent sequences: A153040 A153041 A153042 * A153044 A153045 A153046


KEYWORD

nonn,easy


AUTHOR

Vincenzo Librandi, Dec 17 2008


STATUS

approved



