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 A070592 #28 Apr 03 2025 15:01:11 %S A070592 3,5,17,257,65537,6700417,67280421310721,5704689200685129054721, %T A070592 93461639715357977769163558199606896584051237541638188580280321 %N A070592 Largest prime factor of the n-th Fermat number F(n) = 2^(2^n) + 1. %D A070592 Paulo Ribenboim, The Little Book of Bigger Primes, Springer-Verlag NY 2004. See p. 72. %H A070592 Eric M. Schmidt, <a href="/A070592/b070592.txt">Table of n, a(n) for n = 0..11</a> %H A070592 C. L. Stewart, <a href="https://doi.org/10.1112/plms/s3-35.3.425">On Divisors of Fermat, Fibonacci, Lucas, and Lehmer Numbers</a>, Proceedings of the London Mathematical Society, Vol. s3-35, No. 3 (1977), pp. 425-447. See p. 430. %H A070592 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/FermatNumber.html">Fermat Number</a>. %F A070592 From _Amiram Eldar_, Oct 25 2024: (Start) %F A070592 a(n) = A006530(A000215(n)). %F A070592 a(n) > c * n * 2^n for n >= 1, where c is a positive absolute constant (Stewart, 1977). (End) %o A070592 (PARI) a(n) = vecmax(factor(2^(2^n) + 1)[,1]); \\ _Michel Marcus_, Jul 05 2017 %Y A070592 Cf. A000215, A006530, A050922, A093179. %K A070592 nonn,hard %O A070592 0,1 %A A070592 _Benoit Cloitre_, May 12 2002 %E A070592 Offset changed by _Arkadiusz Wesolowski_, Jul 09 2011