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 A330833 #8 Jan 11 2020 21:40:15 %S A330833 2,2,3,2,5,2,3,17,2,7,41,5,59,2,71,13,89,101,2,17,131,3,167,173,23,29, %T A330833 293,383,5,13,43,677,701,743,17,761,773,827,839,857,911,1091,1097,5, %U A330833 1163,1181,1193,1217,73,1373,1427,79,1487,1559,1583,83,2,1709,1811,1847,1931,1973,2129,2273,2309,2339,2411,2663,2729,2789,2957 %N A330833 a(n) = first prime factor p of the term A330832(n) = p*q. %H A330833 Walter Kehowski, <a href="/A330833/b330833.txt">Table of n, a(n) for n = 1..4731</a> %e A330833 a(5) = 5 and, since A330834(5) = 3, then A330835(5) = (5^3-1)/(5-1) = 31 is prime. %Y A330833 Cf. A003424, A023194, A023195, A085104, A330832, A330834, A330835. %K A330833 nonn,easy %O A330833 1,1 %A A330833 _Walter Kehowski_, Jan 08 2020