Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).
%I #29 Feb 04 2024 01:16:20
%S 5,6,7,9,10,12,13,15,18,19,22,24,25,27,30,33,34,37,39,40,43,45,48,52,
%T 54,55,57,58,60,67,69,72,73,78,79,82,85,87,90,93,94,99,100,102,103,
%U 109,115,117,118,120,123,124,129,132,135,138,139,142,144,145,150,157,159,160
%N Numbers n such that 2n - 7 is a prime.
%D M. Cerasoli, F. Eugeni and M. Protasi, Elementi di Matematica Discreta, Bologna 1988
%D Emanuele Munarini and Norma Zagaglia Salvi, Matematica Discreta, UTET, CittaStudiEdizioni, Milano 1997
%H Shawn A. Broyles, <a href="/A089192/b089192.txt">Table of n, a(n) for n = 1..1000</a>
%t Select[Range[3,200],PrimeQ[2#-7]&] (* _Harvey P. Dale_, Aug 24 2014 *)
%o (PARI) is(n)=isprime(2*n - 7) \\ _Charles R Greathouse IV_, Apr 28 2015
%Y 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).
%Y 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).
%K easy,nonn
%O 1,1
%A _Giovanni Teofilatto_, Dec 08 2003
%E Corrected by _Ralf Stephan_, Mar 03 2004
%E Further correction from _Jeremy Gardiner_, Sep 11 2004