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A177243

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

1, 3, 9, 111, 333, 1467, 6813, 54279, 84573, 252081, 607947, 665667, 1001001, 1110519, 1823841, 3003003, 3129201, 12914001, 13785399, 22161609, 22957083, 37037037, 41089203, 49235049, 64021761, 92840751, 108503721, 111111111

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OFFSET

1,2

LINKS

Table of n, a(n) for n=1..28.

MATHEMATICA

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

CROSSREFS

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

Sequence in context: A018757 A281070 A261245 * A127100 A177793 A018778

Adjacent sequences: A177240 A177241 A177242 * A177244 A177245 A177246

KEYWORD

nonn

AUTHOR

Alexander Adamchuk, May 06 2010

STATUS

approved