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A105421
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Numbers n such that prime(n + 1) == 7 (mod n).
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1
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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
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OFFSET
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1,2
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LINKS
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Table of n, a(n) for n=1..36.
Manfred Scheucher, Sage Script
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MATHEMATICA
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Select[Range[650000], Mod[Prime[#+1]-7, #]==0&] (* Harvey P. Dale, Sep 23 2021 *)
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PROG
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(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
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CROSSREFS
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Cf. A105286, A105287, A105288, A105290, A105329.
Sequence in context: A214700 A100997 A128657 * A273063 A217353 A258194
Adjacent sequences: A105418 A105419 A105420 * A105422 A105423 A105424
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KEYWORD
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nonn
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AUTHOR
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Zak Seidov, May 02 2005
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EXTENSIONS
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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
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STATUS
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approved
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