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A240941
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Numbers k that divide 2^k + 7.
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5
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1, 3, 15, 75, 6308237, 871506915, 2465425275, 2937864075, 2948967789, 83313712623, 195392257275, 11126651718075, 45237726869109, 2920008144904215
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OFFSET
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1,2
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COMMENTS
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Some larger terms: 213736983815110866141, 23423890178454972202084722709155. - Max Alekseyev, Sep 23 2016
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LINKS
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EXAMPLE
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2^3 + 7 = 15 is divisible by 3. Thus 3 is a term of this sequence.
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MATHEMATICA
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k = 1; lst = {1, 3}; While[k < 2500000001, If[ PowerMod[2, k, k] + 7 == k, AppendTo[ lst, k]; Print[ k]]; k += 2]; lst (* Robert G. Wilson v, Aug 05 2014 *)
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PROG
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(PARI)
for(n=1, 10^9, if(Mod(2, n)^n==Mod(-7, n), print1(n, ", ")))
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CROSSREFS
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KEYWORD
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nonn,more,hard
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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