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 A105421 Numbers n such that prime(n + 1) == 7 (mod n). 1
 1, 2, 3, 4, 8, 30, 31, 33, 68, 72, 180, 1052, 6471, 40083, 40087, 40090, 40113, 40120, 100348, 100360, 100362, 637334, 4124588, 10553439, 10553442, 10553455, 10553478, 10553505, 10553512, 10553827, 10553849, 69709712, 69709719, 69709728, 69709958, 21338685404 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Manfred Scheucher, Sage Script MATHEMATICA Select[Range[650000], Mod[Prime[#+1]-7, #]==0&] (* Harvey P. Dale, Sep 23 2021 *) PROG (Python) def A105421(max) : ....terms = [] ....p = 3 ....for n in range(1, max+1) : ........if (p - 7) % n == 0 : terms.append(n) ........p = next_prime(p) ....return terms end # Eric M. Schmidt, Feb 05 2013 (PARI) isok(n) = Mod(prime(n + 1), n) == Mod(7, n); \\ Michel Marcus, Apr 05 2015 (PARI) n=0; forprime(p=3, , if(Mod(p, n++)==7, print1(n", "))) \\ Charles R Greathouse IV, Jul 23 2015 CROSSREFS Cf. A105286, A105287, A105288, A105290, A105329. Sequence in context: A214700 A100997 A128657 * A273063 A217353 A258194 Adjacent sequences:  A105418 A105419 A105420 * A105422 A105423 A105424 KEYWORD nonn AUTHOR Zak Seidov, May 02 2005 EXTENSIONS a(1)-a(4) inserted by Eric M. Schmidt, Feb 05 2013 a(19)-a(22) from Harvey P. Dale, Apr 05 2015 a(23)-a(35) from Manfred Scheucher, Jul 23 2015 a(36) from Charles R Greathouse IV, Jul 23 2015 STATUS approved

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Last modified May 26 17:16 EDT 2022. Contains 354092 sequences. (Running on oeis4.)