%I #19 Sep 29 2024 02:43:02

%S 6,14,42,526974,9157582,21001206,49419154,156418318,157058362,

%T 223741702,467016562,531330346,601692022,681377698,888739174,

%U 931053466,1037629198,1390950926,1392718618,2175608494,2377982166,3045063946,5136468646

%N Even pseudoprimes to base 43.

%H Amiram Eldar, <a href="/A130443/b130443.txt">Table of n, a(n) for n = 1..74</a> (terms below 10^11; terms 1..46 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[43, 2n - 1, 2n] == 1, AppendTo[lst, 2n]], {n, 2, 1800000000}]; lst (* _Robert G. Wilson v_, Jun 01 2007 *)

%o (PARI) is(k) = k > 2 && !(k % 2) && Mod(43, k)^(k-1) == 1; \\ _Amiram Eldar_, Sep 29 2024

%Y Cf. A020171, A006935, A130433, A090082, A090083, A090084, A090085, A130434, A130435, A130436, A130437, A130438, A130439, A130440, A130441, A130442.

%K nonn

%O 1,1

%A _Alexander Adamchuk_, May 26 2007, Jun 20 2007

%E More terms from _Robert G. Wilson v_, Jun 01 2007