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A030432 Primes of form 10n+7. 43
7, 17, 37, 47, 67, 97, 107, 127, 137, 157, 167, 197, 227, 257, 277, 307, 317, 337, 347, 367, 397, 457, 467, 487, 547, 557, 577, 587, 607, 617, 647, 677, 727, 757, 787, 797, 827, 857, 877, 887, 907, 937, 947, 967, 977, 997, 1087, 1097, 1117, 1187, 1217, 1237 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Union of A132231 and A039949. - Ray Chandler, Apr 07 2009
5 is not quadratic residue of primes of this form. - Vincenzo Librandi, Jun 25 2014
Also primes of the form 5n+2 with positive n. - Danny Rorabaugh, Feb 20 2016
Intersection of A000040 and A017353. - Iain Fox, Dec 30 2017
LINKS
A. Granville and G. Martin, Prime number races, arXiv:math/0408319 [math.NT], 2004.
FORMULA
a(n) = 10*A102342(n) + 7.
a(n) ~ 4n log n. - Charles R Greathouse IV, Jul 01 2013
MATHEMATICA
Select[Prime@Range[210], Mod[ #, 10] == 7 &] (* Ray Chandler, Nov 07 2006 *)
PROG
(Magma) [n: n in [7..1240 by 10] | IsPrime(n)]; // Bruno Berselli, Apr 06 2011
(PARI) is(n)=n%10==7 && isprime(n) \\ Charles R Greathouse IV, Jul 01 2013
(PARI) lista(nn) = forprime(p=7, nn, if(p%10==7, print1(p, ", "))) \\ Iain Fox, Dec 30 2017
(Sage) [10*n+7 for n in range(124) if is_prime(10*n+7)] # Danny Rorabaugh, Feb 20 2016
CROSSREFS
Cf. A030430 (10n+1), A030431 (10n+3), A030433 (10n+9).
Sequence in context: A257668 A106095 A153319 * A090147 A348560 A338030
KEYWORD
nonn,easy,base
AUTHOR
EXTENSIONS
Extended by Ray Chandler, Nov 07 2006
STATUS
approved

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Last modified July 23 15:54 EDT 2024. Contains 374552 sequences. (Running on oeis4.)