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A276740
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Numbers n such that 3^n == 5 (mod n).
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9
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1, 2, 4, 76, 418, 1102, 4687, 7637, 139183, 2543923, 1614895738, 9083990938, 23149317409, 497240757797, 4447730232523, 16000967516764, 65262766108619, 141644055557882
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OFFSET
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1,2
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COMMENTS
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No other terms below 10^15. Some larger terms: 194995887252090239, 2185052151122686482926861593785262. - Max Alekseyev, Oct 13 2016
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LINKS
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Table of n, a(n) for n=1..18.
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EXAMPLE
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3 == 5 (mod 1), so 1 is a term;
9 == 5 (mod 2), so 2 is a term.
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MATHEMATICA
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Select[Range[10^7], PowerMod[3, #, #] == Mod[5, #] &] (* Michael De Vlieger, Sep 26 2016 *)
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PROG
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(PARI) isok(n) = Mod(3, n)^n == Mod(5, n); \\ Michel Marcus, Sep 17 2016
(Python)
A276740_list = [1, 2, 4]+[n for n in range(5, 10**6) if pow(3, n, n) == 5] # Chai Wah Wu, Oct 04 2016
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CROSSREFS
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Cf. A066601.
Solutions to 3^n == k (mod n): A277340 (k=-11), A277289 (k=-7), A277288 (k=-5), A015973 (k=-2), A015949 (k=-1), A067945 (k=1), A276671 (k=2), this sequence (k=5), A277628 (k=6), A277126 (k=7), A277630 (k=8), A277274 (k=11).
Sequence in context: A053550 A018378 A023175 * A006688 A292711 A018389
Adjacent sequences: A276737 A276738 A276739 * A276741 A276742 A276743
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KEYWORD
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nonn,more
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AUTHOR
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Dmitry Ezhov, Sep 16 2016
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EXTENSIONS
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a(11)-a(13) from Chai Wah Wu, Oct 05 2016
a(14) from Lars Blomberg, Oct 12 2016
a(15)-a(18) from Max Alekseyev, Oct 13 2016
a(12) was missing Robert G. Wilson v, Oct 19 2016
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STATUS
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approved
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