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A089192
Numbers n such that 2n - 7 is a prime.
25
5, 6, 7, 9, 10, 12, 13, 15, 18, 19, 22, 24, 25, 27, 30, 33, 34, 37, 39, 40, 43, 45, 48, 52, 54, 55, 57, 58, 60, 67, 69, 72, 73, 78, 79, 82, 85, 87, 90, 93, 94, 99, 100, 102, 103, 109, 115, 117, 118, 120, 123, 124, 129, 132, 135, 138, 139, 142, 144, 145, 150, 157, 159, 160
OFFSET
1,1
REFERENCES
M. Cerasoli, F. Eugeni and M. Protasi, Elementi di Matematica Discreta, Bologna 1988
Emanuele Munarini and Norma Zagaglia Salvi, Matematica Discreta, UTET, CittaStudiEdizioni, Milano 1997
LINKS
MATHEMATICA
Select[Range[3, 200], PrimeQ[2#-7]&] (* Harvey P. Dale, Aug 24 2014 *)
PROG
(PARI) is(n)=isprime(2*n - 7) \\ Charles R Greathouse IV, Apr 28 2015
CROSSREFS
Numbers n such that 2n+k is prime: A005097 (k=1), A067076 (k=3), A089038 (k=5), A105760 (k=7), A155722 (k=9), A101448 (k=11), A153081 (k=13), A089559 (k=15), A173059 (k=17), A153143 (k=19).
Numbers n such that 2n-k is prime: A006254 (k=1), A098090 (k=3), A089253 (k=5), this sequence (k=7), A097069 (k=9), A097338 (k=11), A097363 (k=13), A097480 (k=15), A098605 (k=17), A097932 (k=19).
Sequence in context: A066263 A178096 A246782 * A279195 A232710 A132829
KEYWORD
easy,nonn
AUTHOR
Giovanni Teofilatto, Dec 08 2003
EXTENSIONS
Corrected by Ralf Stephan, Mar 03 2004
Further correction from Jeremy Gardiner, Sep 11 2004
STATUS
approved