

A153041


Numbers n >=10 such that 2*n19 is not a prime.


4



10, 14, 17, 20, 22, 23, 26, 27, 29, 32, 34, 35, 37, 38, 41, 42, 44, 47, 48, 50, 52, 53, 55, 56, 57, 59, 62, 65, 67, 68, 69, 70, 71, 72, 74, 76, 77, 80, 81, 82, 83, 86, 87, 89, 90, 92, 94, 95, 97, 98, 101, 102, 103, 104
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OFFSET

1,1


COMMENTS

One more than associated values in A153051, two more than A153047.  R. J. Mathar, Jan 05 2011
The terms after a(1) are the values of 2*h*k + k + h + 10, 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[10, 200], !PrimeQ[2 #  19] &] (* Vincenzo Librandi, Jan 19 2013 *)


PROG

(MAGMA) [n: n in [10..150]  not IsPrime(2*n  19)]; // Vincenzo Librandi, Jan 19 2013


CROSSREFS

Cf. A097932, A155704.
Numbers n such that 2nk is not prime: A104275 (k=1), A153043 (k=3), A153040 (k=5), A153039 (k=7), A153044 (k=9), A153045 (k=11), A153049 (k=13), A153047 (k=15), A153051 (k=17), A153041 (k=19).
Similar sequence listed also in A089559, A153144.
Sequence in context: A055197 A116610 A289698 * A256471 A250403 A096851
Adjacent sequences: A153038 A153039 A153040 * A153042 A153043 A153044


KEYWORD

nonn,easy


AUTHOR

Vincenzo Librandi, Dec 17 2008


EXTENSIONS

Edited by N. J. A. Sloane, Jun 22 2010


STATUS

approved



