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%I #45 Sep 08 2022 08:44:50
%S 7,17,37,47,67,97,107,127,137,157,167,197,227,257,277,307,317,337,347,
%T 367,397,457,467,487,547,557,577,587,607,617,647,677,727,757,787,797,
%U 827,857,877,887,907,937,947,967,977,997,1087,1097,1117,1187,1217,1237
%N Primes of form 10n+7.
%C Union of A132231 and A039949. - _Ray Chandler_, Apr 07 2009
%C 5 is not quadratic residue of primes of this form. - _Vincenzo Librandi_, Jun 25 2014
%C Also primes of the form 5n+2 with positive n. - _Danny Rorabaugh_, Feb 20 2016
%C Intersection of A000040 and A017353. - _Iain Fox_, Dec 30 2017
%H Michael B. Porter, <a href="/A030432/b030432.txt">Table of n, a(n) for n = 1..100000</a>
%H A. Granville and G. Martin, <a href="https://arxiv.org/abs/math/0408319">Prime number races</a>, arXiv:math/0408319 [math.NT], 2004.
%F a(n) = 10*A102342(n) + 7.
%F a(n) ~ 4n log n. - _Charles R Greathouse IV_, Jul 01 2013
%t Select[Prime@Range[210], Mod[ #, 10] == 7 &] (* _Ray Chandler_, Nov 07 2006 *)
%o (Magma) [n: n in [7..1240 by 10] | IsPrime(n)]; // _Bruno Berselli_, Apr 06 2011
%o (PARI) is(n)=n%10==7 && isprime(n) \\ _Charles R Greathouse IV_, Jul 01 2013
%o (PARI) lista(nn) = forprime(p=7, nn, if(p%10==7, print1(p, ", "))) \\ _Iain Fox_, Dec 30 2017
%o (Sage) [10*n+7 for n in range(124) if is_prime(10*n+7)] # _Danny Rorabaugh_, Feb 20 2016
%Y Cf. A030430 (10n+1), A030431 (10n+3), A030433 (10n+9).
%Y Cf. A045357, A045380, A049509, A102342.
%K nonn,easy,base
%O 1,1
%A _Warut Roonguthai_
%E Extended by _Ray Chandler_, Nov 07 2006
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