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Smallest prime == 1 mod (7n).
9

%I #12 Apr 13 2022 09:40:16

%S 29,29,43,29,71,43,197,113,127,71,463,337,547,197,211,113,239,127,

%T 1597,281,883,463,967,337,701,547,379,197,2437,211,1303,449,463,239,

%U 491,757,2591,1597,547,281,1723,883,3011,617,631,967,659,337,1373,701,1429

%N Smallest prime == 1 mod (7n).

%H Harvey P. Dale, <a href="/A070851/b070851.txt">Table of n, a(n) for n = 1..500</a>

%t Module[{nn=60,prs=Prime[Range[500]]},Table[SelectFirst[prs,Mod[#,7n]==1&],{n,nn}]] (* _Harvey P. Dale_, Apr 13 2022 *)

%o (PARI) for(n=1,80,s=1; while((isprime(s)*s-1)%(7*n)>0,s++); print1(s,","))

%Y Cf. A070846 to A070850 and A070852, A070853.

%Y Cf. A034694.

%K nonn

%O 1,1

%A _Amarnath Murthy_, May 15 2002

%E More terms from _Benoit Cloitre_, May 18 2002