A020183 Pseudoprimes to base 55.

6, 9, 18, 21, 27, 54, 63, 91, 153, 189, 357, 369, 553, 697, 801, 1027, 1266, 1387, 1513, 1729, 1869, 2701, 2821, 3213, 3649, 4033, 4431, 6273, 6533, 6541, 6601, 6643, 7189, 7957, 8911, 9773, 9937, 10649, 10761, 13333, 13617, 13833, 14981, 15457, 15841

Offset

1,1

Comments

Composite numbers n such that 55^(n-1) == 1 (mod n).

Links

T. D. Noe, Table of n, a(n) for n = 1..1000

Index entries for sequences related to pseudoprimes

Mathematica

base = 55; 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[16000], CompositeQ[#]&&PowerMod[55, #-1, #]==1&] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Oct 26 2018 *)

Crossrefs

Cf. A001567 (pseudoprimes to base 2).

Sequence in context: A351851 A301720 A316070 * A320492 A316071 A039280

Adjacent sequences: A020180 A020181 A020182 * A020184 A020185 A020186

Keyword

nonn

Author

David W. Wilson

Status

approved