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A128368
a(n) = least k such that the remainder when 28^k is divided by k is n.
17
3, 13, 5, 6, 23, 11, 15, 194, 19, 18, 17, 148, 213, 22, 131209, 20, 2335, 25, 7311, 44, 259, 51, 5263, 38, 21927, 758, 240055, 29, 803, 58, 21921, 55, 4405, 39, 413, 316, 549, 746, 17831, 62, 4367, 106, 165, 74, 19253, 82, 6455, 88, 147, 734, 62093, 122
OFFSET
1,1
MATHEMATICA
t = Table[0, {10000} ]; k = 1; While[ k < 5000000000, a = PowerMod[28, k, k]; If[a < 10001 && t[[a]] == 0, t[[a]] = k; Print[{a, k}]]; k++ ]; t (* Robert G. Wilson v, Aug 06 2009 *)
KEYWORD
hard,nonn
AUTHOR
Alexander Adamchuk, Feb 27 2007
STATUS
approved