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 A122691 #8 May 25 2024 21:06:19 %S A122691 127,401,19,53,151,7,139,127,19,78721,3458771,19,7,38954263,19,79,53, %T A122691 19,157,7,19,127,18191,19,12119,421,7, %U A122691 107434435760557861791327959267859939351202240879711219728393537522815146155523913,79,19,23196834569628410341642097660316821 %N A122691 a(n) is the least prime factor of (9 * 10^(6*n-4) - 11) / 7. %H A122691 Sean A. Irvine, <a href="/A122691/b122691.txt">Table of n, a(n) for n = 1..69</a> %e A122691 n=2, (9*10^8-11)/7 = 128571427 = 401 * 320627 hence a(2)=401. %Y A122691 Cf. A100275, A122862. %K A122691 nonn %O A122691 1,1 %A A122691 _Zak Seidov_, Sep 22 2006 %E A122691 a(28) onward corrected by _Sean A. Irvine_, May 25 2024