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Primes p such that q*p+-Mod(p,q) are primes, for q=7.
1

%I #4 Feb 13 2019 16:23:31

%S 41,419,839,1259,1889,2239,3541,4801,5039,5711,6229,7349,7699,7741,

%T 9239,10429,10891,11171,11801,12809,13159,14629,15889,16631,16981,

%U 17891,18661,18899,20089,21559,21601,22651,22679,23981,24989,25969,26879

%N Primes p such that q*p+-Mod(p,q) are primes, for q=7.

%C 7*41=287+-6->primes,..

%t q=7;lst={};Do[p=Prime[n];If[PrimeQ[q*p-Mod[p,q]]&&PrimeQ[q*p+Mod[p,q]],AppendTo[lst,p]],{n,8!}];lst

%t Select[Prime[Range[3000]],AllTrue[7#+{Mod[#,7],-Mod[#,7]},PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* _Harvey P. Dale_, Feb 13 2019 *)

%Y Cf. A000040, A178383, A178385, A178386

%K nonn

%O 1,1

%A _Vladimir Joseph Stephan Orlovsky_, May 26 2010