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 A177243 Numbers k such that k^3 divides 10^(k^2) - 1. 15

%I #8 Jun 06 2021 09:02:38

%S 1,3,9,111,333,1467,6813,54279,84573,252081,607947,665667,1001001,

%T 1110519,1823841,3003003,3129201,12914001,13785399,22161609,22957083,

%U 37037037,41089203,49235049,64021761,92840751,108503721,111111111

%N Numbers k such that k^3 divides 10^(k^2) - 1.

%t Join[{1},Select[Range[1112*10^5],PowerMod[10,#^2,#^3]==1&]] (* _Harvey P. Dale_, Sep 10 2019 *)

%Y Cf. A127100 (k^2 divides 10^k-1), A014950 (k divides 10^k-1).

%K nonn

%O 1,2

%A _Alexander Adamchuk_, May 06 2010

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Last modified February 26 10:22 EST 2024. Contains 370342 sequences. (Running on oeis4.)