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Even pseudoprimes to base 17.
15

%I #27 Sep 19 2024 01:50:07

%S 4,8,16,1228,4912,5662,11476,76798,168904,387676,938792,1003276,

%T 1147576,1415044,1419856,1832836,2297296,3976624,5470126,6376126,

%U 7309576,9649624,12423676,13193776,14026888,14652496,19136272,20570936,24604696

%N Even pseudoprimes to base 17.

%H Amiram Eldar, <a href="/A130436/b130436.txt">Table of n, a(n) for n = 1..400</a> (terms 1..119 from Robert G. Wilson v)

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/FermatPseudoprime.html">Fermat Pseudoprime</a>.

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

%t lst = {}; Do[ If[ PowerMod[17, 2n - 1, 2n] == 1, AppendTo[lst, 2n]], {n, 2, 2*10^9}]; lst (* _Robert G. Wilson v_, Jun 01 2007 *)

%o (PARI) is(k) = k > 2 && !(k % 2) && Mod(17, k)^(k-1) == 1; \\ _Amiram Eldar_, Sep 18 2024

%Y Cf. A020145, A006935, A130433, A090082, A090083, A090084, A090085, A130434, A130435, A130437, A130438, A130439, A130440, A130441, A130442, A130443.

%K nonn

%O 1,1

%A _Alexander Adamchuk_, May 26 2007

%E a(13)-a(29) from _Robert G. Wilson v_, Jun 01 2007