A020190 - OEIS

A020190

Pseudoprimes to base 62.

9, 21, 45, 63, 91, 105, 183, 231, 305, 361, 427, 549, 561, 671, 679, 703, 793, 861, 1105, 1261, 1281, 1541, 1729, 2121, 2465, 2501, 2745, 2871, 3367, 3439, 3843, 3845, 4141, 4187, 4577, 5185, 5307, 5551, 5565, 5901, 5917, 6161, 6405, 6533, 6601, 6697, 6849

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OFFSET

1,1

COMMENTS

Composite numbers k such that 62^(k-1) == 1 (mod k). - 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

base = 62; 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], CompositeQ[#]&&PowerMod[62, #-1, #]==1&] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Jul 20 2019 *)

CROSSREFS