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Pseudoprimes to base 49.
1

%I #13 Aug 03 2014 14:01:11

%S 4,6,8,12,15,16,24,25,48,66,75,76,172,176,232,247,276,304,325,425,435,

%T 475,496,559,561,688,703,817,904,946,949,1075,1105,1128,1146,1695,

%U 1825,1891,2101,2353,2356,2465,2486,2509,2701,3056,3091,3268,3277,3439

%N Pseudoprimes to base 49.

%C Composite numbers n such that 49^(n-1) == 1 (mod n).

%H T. D. Noe, <a href="/A020177/b020177.txt">Table of n, a(n) for n = 1..1000</a>

%H <a href="/index/Ps#pseudoprimes">Index entries for sequences related to pseudoprimes</a>

%t base = 49; 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 *)

%Y Cf. A001567 (pseudoprimes to base 2).

%K nonn

%O 1,1

%A _David W. Wilson_