A116636 - OEIS

A116636

Positive integers k such that 13^k == 9 (mod k).

1, 2, 4, 8, 10, 172, 296, 332, 410, 872, 1048, 1070, 1544, 2830, 3470, 7486, 9196, 22184, 90892, 121174, 299816, 575206, 885112, 1329388, 1386430, 2518994, 4167272, 5600212, 8475016, 9180370, 12348446, 18483076, 19185890, 20806274, 28984094, 37114141

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OFFSET

1,2

COMMENTS

For k > 9 in this sequence, A116609(k) = 9. - Iain Fox, Nov 20 2017

LINKS

Max Alekseyev, Table of n, a(n) for n = 1..112

MATHEMATICA

Join[{1, 2, 4, 8}, Select[Range[1, 9000], Mod[13^#, #] == 9 &]] (* G. C. Greubel, Nov 19 2017 *)

PROG

(PARI) isok(n) = Mod(13, n)^n == 9; \\ Michel Marcus, Nov 19 2017

CROSSREFS

Solutions to 13^n == k (mod n): A001022 (k=0), A015963 (k=-1), A116621 (k=1), A116622 (k=2), A116629 (k=3), A116630 (k=4), A116611 (k=5), A116631 (k=6), A116632 (k=7), A295532 (k=8), this sequence (k=9), A116620 (k=10), A116638 (k=11), A116639 (k=15).

Cf. A116609.

Sequence in context: A331027 A210108 A217131 * A256980 A014425 A372935

Adjacent sequences: A116633 A116634 A116635 * A116637 A116638 A116639

KEYWORD

nonn

AUTHOR

Zak Seidov, Feb 19 2006

EXTENSIONS

More terms from Ryan Propper, Nov 05 2006

Terms 1,2,4,8 prepended by Max Alekseyev, Jun 28 2011

STATUS

approved