A116620 Positive integers n such that 13^n == 10 (mod n).

1, 3, 9, 74853, 1275039, 27181907, 31261887, 989255061, 4813809711, 3187842157567, 313768710194691

Offset: 1

Author

Zak Seidov, Feb 19 2006

Keywords

• more
• nonn

Comments

No other terms below 10^15. - Max Alekseyev, Nov 06 2018

9909932321420413420533943 is a term. - Max Alekseyev, Jun 29 2011

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), A116636 (k=9), this sequence (k=10), A116638 (k=11), A116639 (k=15).

Cf. A116609.

Programs

Mathematica

Join[{1, 3, 9}, Select[Range[2000000], PowerMod[13, #, #] == 10 &]] (* Robert Price, Apr 10 2020 *)

Extensions

More terms from Ryan Propper, Jun 12 2006

Terms 1,3,9 prepended and a(10)-a(11) added by Max Alekseyev, Jun 29 2011, Nov 06 2018