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A020196 Pseudoprimes to base 68. 1
25, 49, 69, 91, 125, 133, 185, 201, 217, 247, 325, 345, 361, 403, 469, 481, 589, 637, 805, 871, 925, 931, 1005, 1025, 1221, 1225, 1273, 1417, 1519, 1541, 1725, 1729, 1771, 1813, 2077, 2185, 2211, 2413, 2527, 2553, 2665, 2725, 2821, 3283, 3325, 3565, 4033, 4123 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Composite numbers n such that 68^(n-1) == 1 (mod n). - Michel Lagneau, Feb 18 2012

LINKS

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

Index entries for sequences related to pseudoprimes

MATHEMATICA

max = 5000; Select[Complement[Range[max], Prime[Range[PrimePi[max]]]], PowerMod[68, # - 1, #] == 1 &] (* Alonso del Arte, Jun 17 2018 *)

CROSSREFS

Cf. A001567 (pseudoprimes to base 2).

Sequence in context: A322121 A020146 A020244 * A020294 A103214 A067778

Adjacent sequences:  A020193 A020194 A020195 * A020197 A020198 A020199

KEYWORD

nonn

AUTHOR

David W. Wilson

STATUS

approved

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Last modified April 23 13:25 EDT 2019. Contains 322386 sequences. (Running on oeis4.)