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a(n) = least k such that the remainder when 12^k is divided by k is n.
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%I #15 Mar 08 2024 09:01:45

%S 11,5,15,10,7,21,25,34,549,134,120593747,13,20395,26,1713,20,203,57,

%T 49,62,1707,122,55,30,793,118,45,58,1921,38,1853,56,339,110,4223,42,

%U 85,106,1689,52,841,642,4475,70,51,551,11683,147,168061,94,129,623,1243895,90

%N a(n) = least k such that the remainder when 12^k is divided by k is n.

%H Robert G. Wilson v, <a href="/A127820/a127820.txt">Table of n, a(n) for n = 1..10000 with -1 for large entries where a(n) has not yet been found</a>

%t t = Table[0, {10000} ]; k = 1; While[ k < 3000000000, a = PowerMod[12, k, k]; If[a < 10001 && t[[a]] == 0, t[[a]] = k; Print[{a, k}]]; k++ ]; t (* _Robert G. Wilson v_, Aug 04 2009 *)

%Y Cf. A036236, A078457, A119678, A119679, A127816, A119715, A119714, A127817, A127818, A127819, A127821.

%K nonn

%O 1,1

%A _Alexander Adamchuk_, Jan 30 2007

%E More terms from _Robert G. Wilson v_, Feb 06 2007