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Pseudoprimes to base 79.
1

%I #16 Feb 15 2015 19:31:42

%S 6,15,26,39,49,65,78,91,195,301,559,561,637,1105,1649,1729,2107,2465,

%T 2626,2665,2701,2821,3201,3913,4215,4753,5055,6305,6533,6601,7051,

%U 7107,7361,7543,8149,8321,8911,9331,9773,9881,10585,10621,12001,14491,14689

%N Pseudoprimes to base 79.

%C Composite numbers n such that 79^(n-1) == 1 (mod n).

%H T. D. Noe, <a href="/A020207/b020207.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 = 79; 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 *)

%t Select[Range[15000],CompositeQ[#]&&PowerMod[79,#-1,#]==1&] (* _Harvey P. Dale_, Feb 15 2015 *)

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

%K nonn

%O 1,1

%A _David W. Wilson_