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 A056754 Numbers n such that n | 9^n + 8^n + 7^n + 6^n + 5^n + 4^n + 3^n + 2^n + 1^n. 0

%I

%S 1,3,5,9,15,25,27,45,75,81,125,135,225,243,375,405,423,625,675,729,

%T 765,801,895,1017,1125,1175,1215,1875,2025,2125,2187,3125,3375,3645,

%U 4755,5625,6075,6561,9375,9585,10125,10935,15625,16875,17925,18225,19683

%N Numbers n such that n | 9^n + 8^n + 7^n + 6^n + 5^n + 4^n + 3^n + 2^n + 1^n.

%t Do[ If[ Mod[ PowerMod[ 9, n, n ] + PowerMod[ 8, n, n ] + PowerMod[ 7, n, n ] + PowerMod[ 6, n, n ] + PowerMod[ 5, n, n ] + PowerMod[ 4, n, n ] + PowerMod[ 3, n, n ] + PowerMod[ 2, n, n ] + 1, n ] == 0, Print[ n ] ], {n, 1, 10^6} ]

%t Select[Range[20000],Divisible[Total[Range[2,9]^# ]+1,#]&] (* _Harvey P. Dale_, Oct 09 2019 *)

%Y Cf. A001556.

%K nonn

%O 1,2

%A _Robert G. Wilson v_, Aug 25 2000

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Last modified January 24 19:34 EST 2022. Contains 350565 sequences. (Running on oeis4.)