A020219 - OEIS

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A020219

Pseudoprimes to base 91.

6, 9, 10, 15, 18, 30, 45, 66, 69, 90, 115, 205, 207, 341, 345, 369, 435, 505, 561, 909, 1035, 1065, 1387, 1446, 1541, 1845, 2047, 2059, 2465, 2651, 2701, 2829, 2871, 3015, 4005, 4141, 4187, 4371, 4545, 5963, 6273, 6533, 6969, 7471, 8646, 9361, 9881, 10585

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OFFSET

1,1

COMMENTS

Composite numbers n such that 91^(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 = 91; 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[11000], CompositeQ[#]&&PowerMod[91, #-1, #]==1&] (* Harvey P. Dale, Aug 15 2017 *)

CROSSREFS