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A153039 Numbers n such that 2*n-7 is composite. 6
8, 11, 14, 16, 17, 20, 21, 23, 26, 28, 29, 31, 32, 35, 36, 38, 41, 42, 44, 46, 47, 49, 50, 51, 53, 56, 59, 61, 62, 63, 64, 65, 66, 68, 70, 71, 74, 75, 76, 77, 80, 81, 83, 84, 86, 88, 89, 91, 92, 95, 96, 97, 98, 101, 104, 105, 106, 107, 108, 110, 111, 112 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Two more than the associated value in A153043, one more than in A153040.

LINKS

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

MATHEMATICA

Select[Range[8, 200], !PrimeQ[2*#-7]&] (* Vladimir Joseph Stephan Orlovsky, Feb 09 2012 *)

PROG

(MAGMA) [n: n in [5..220]| not IsPrime(2*n-7)]

(PARI) list(n)=apply(k->(k+7)/2, setminus(vector(n, k, 2*k+7), primes(primepi(2*n+7)))) \\ Charles R Greathouse IV, May 14 2012

CROSSREFS

Complement of A089192, A153040.

Sequence in context: A308562 A254671 A265412 * A190208 A061570 A096679

Adjacent sequences:  A153036 A153037 A153038 * A153040 A153041 A153042

KEYWORD

nonn,easy

AUTHOR

Vincenzo Librandi, Dec 17 2008

EXTENSIONS

Partially edited by N. J. A. Sloane, Jun 23 2010

STATUS

approved

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Last modified November 21 04:41 EST 2019. Contains 329350 sequences. (Running on oeis4.)