This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A130439 #16 Feb 16 2025 08:33:06
%S A130439 4,14,28,52,268,364,1876,3484,5356,7294,24388,66788,283276,286492,
%T A130439 339556,404236,860692,1153684,1381132,1478764,1696708,2073722,2182726,
%U A130439 2222122,4922164,7790146,8200036,9679138,10881052,14863516,15476266
%N A130439 Even pseudoprimes to base 29.
%H A130439 Amiram Eldar, <a href="/A130439/b130439.txt">Table of n, a(n) for n = 1..279</a> (terms below 10^11; terms 1..121 from Robert G. Wilson v)
%H A130439 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/FermatPseudoprime.html">Fermat Pseudoprime</a>.
%H A130439 <a href="/index/Ps#pseudoprimes">Index entries for sequences related to pseudoprimes</a>.
%t A130439 Do[ f=PowerMod[ 29, 2n-1, 2n ]; If[ f==1, Print[ 2n ] ], {n,2,500000} ]
%t A130439 lst = {}; Do[ If[ PowerMod[17, 2n - 1, 2n] == 1, AppendTo[lst, 2n]], {n, 2, 2^31}]; lst (* _Robert G. Wilson v_, Jun 01 2007 *)
%o A130439 (PARI) is(k) = k > 2 && !(k % 2) && Mod(29, k)^(k-1) == 1; \\ _Amiram Eldar_, Sep 29 2024
%Y A130439 Cf. A020157, A006935, A130433, A090082, A090083, A090084, A090085, A130434, A130435, A130436, A130437, A130438, A130440, A130441, A130442, A130443.
%K A130439 nonn
%O A130439 1,1
%A A130439 _Alexander Adamchuk_, May 26 2007
%E A130439 More terms from _Robert G. Wilson v_, Jun 01 2007