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 A055386 #28 Jun 02 2025 04:59:45
%S A055386 5,257,13,97,101,89,29,274177,5,148721,5,17,53,449,17,641,13,17,5,17,
%T A055386 5,41,29,769,41,89,13,17,5,17,5,59649589127497217,37,41,13,97,149,17,
%U A055386 5,15361,5,1753,13,17,41,449,1129,1153,5,17,5,1201,17,1777,89,4993,41
%N A055386 Smallest factor of (2n)^(2n) + 1.
%C A055386 If we use the commonly accepted convention that 0^0 = 1, then a(0) = 2. - _Chai Wah Wu_, Jul 22 2019
%D A055386 C. Stanley Ogilvy and John T. Anderson, Excursions in Number Theory. Dover. New York: 1988. Page 82.
%H A055386 Chai Wah Wu, <a href="/A055386/b055386.txt">Table of n, a(n) for n = 1..313</a>
%H A055386 <a href="http://cage.rug.ac.be/~hvernaev/problems/Proble36.html">Is there any value of n other than 1, 2 and 4, such that n^n+1 is a prime? </a>
%F A055386 a(n) = A055385(2*n). - _Michel Marcus_, Jul 23 2013
%e A055386 8^8 + 1 = 97 * 257 * 673, so a(4) = 97.
%t A055386 Table[With[{k = 2 n}, FactorInteger[k^k + 1]][[1, 1]], {n, 1, 60, 1}] (* _Vincenzo Librandi_, Jul 23 2013 *)
%o A055386 (PARI) a(n) = factor((2*n)^(2*n) + 1)[1, 1] \\ _Michel Marcus_, Jul 23 2013; corrected by _Jason Yuen_, Jun 01 2025
%Y A055386 Cf. A014566, A055385.
%K A055386 nonn
%O A055386 1,1
%A A055386 _Walter Nissen_, Jun 24 2000