A130443 Even pseudoprimes to base 43.

6, 14, 42, 526974, 9157582, 21001206, 49419154, 156418318, 157058362, 223741702, 467016562, 531330346, 601692022, 681377698, 888739174, 931053466, 1037629198, 1390950926, 1392718618, 2175608494, 2377982166, 3045063946, 5136468646

Offset: 1

Author

Alexander Adamchuk, May 26 2007, Jun 20 2007

Keywords

• nonn

Links

• Amiram Eldar, Table of n, a(n) for n = 1..74 (terms below 10^11; terms 1..46 from Robert G. Wilson v)
• Eric Weisstein's World of Mathematics, Fermat Pseudoprime.
• Index entries for sequences related to pseudoprimes.

Crossrefs

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

Programs

Mathematica

lst = {}; Do[ If[ PowerMod[43, 2n - 1, 2n] == 1, AppendTo[lst, 2n]], {n, 2, 1800000000}]; lst (* Robert G. Wilson v, Jun 01 2007 *)

PARI

is(k) = k > 2 && !(k % 2) &&  Mod(43, k)^(k-1) == 1; \\ Amiram Eldar, Sep 29 2024

Extensions

More terms from Robert G. Wilson v, Jun 01 2007