A128159 a(n) = least k such that the remainder when 19^k is divided by k is n.

2, 17, 358, 5, 7, 13, 118, 11, 22, 207, 14, 6683, 21, 1055, 221, 6843, 86, 39959, 23, 559, 34, 129, 26, 25, 51, 799, 334, 33, 166, 47427581, 1537, 901, 68, 39, 326, 87169, 44, 161, 46, 3509, 341, 529, 106, 1098179, 158, 657, 314, 49621349, 75, 143, 62, 749, 116

Offset

1,1

Comments

a(447) = 7987803178, a(660) = 11147676413, a(923) = 6246715274. - Daniel Morel, Jun 08 2010

a(216) = 21686254249, a(296) = 40778012377, a(386) = 15891209603, a(582) = 46530896443, a(638) = 15297472657, a(736) = 45211411479, a(872) = 106458212591. - Daniel Morel, Oct 15 2010

Links

Table of n, a(n) for n=1..53.

Robert G. Wilson v, Table of n, a(n) for n = 1..10000 with -1 for large entries where a(n) has not yet been found

Mathematica

t = Table[0, {10000} ]; k = 1; While[ k < 3100000000, a = PowerMod[19, k, k]; If[a < 10001 && t[[a]] == 0, t[[a]] = k; Print[{a, k}]]; k++ ]; t (* Robert G. Wilson v, Aug 04 2009 *)
clk=Compile[{{n, _Integer}}, {k=1}; While[PowerMod[19, k, k]!=n, k++]; k]; Array[ clk, 55] (* Harvey P. Dale, May 10 2014 *)

Crossrefs

Cf. A036236, A078457, A119678, A119679, A127816, A119715, A119714, A127817, A127818, A127819, A127820, A127821, A128154, A128155, A128156, A128157, A128158, A128160.

Cf. A128149, A128150.

Sequence in context: A373324 A330260 A243509 * A319591 A198405 A202972

Adjacent sequences: A128156 A128157 A128158 * A128160 A128161 A128162

Keyword

hard,nonn

Author

Alexander Adamchuk, Feb 16 2007

Extensions

More terms from Ryan Propper, Mar 24 2007

More terms from Robert G. Wilson v, Aug 04 2009

Status

approved