A020171 Pseudoprimes to base 43.

6, 14, 21, 25, 33, 42, 77, 91, 105, 165, 185, 231, 325, 385, 425, 481, 525, 561, 777, 825, 861, 925, 973, 1045, 1105, 1221, 1541, 1729, 1785, 1807, 1825, 1925, 2071, 2425, 2465, 2553, 2821, 2849, 3145, 3281, 3439, 3781, 3885, 4033, 4417, 4825, 5005, 5565, 6105

Offset: 1

Author

David W. Wilson

Keywords

• nonn

Comments

Composite numbers n such that 43^(n-1) == 1 (mod n).

Links

• R. J. Mathar, Table of n, a(n) for n=1..1234
• Index entries for sequences related to pseudoprimes

Crossrefs

Cf. A001567 (pseudoprimes to base 2).

Programs

Mathematica

base = 43; t = {}; n = 1; While[Length[t] < 100, n++; If[! PrimeQ[n] && PowerMod[base, n-1, n] == 1, AppendTo[t, n]]]; t (* T. D. Noe, Feb 21 2012 *)
Select[Range[7000],!PrimeQ[#]&&PowerMod[43,#-1,#]==1&] (* Harvey P. Dale, Aug 17 2017 *)