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 A231969 #4 Nov 18 2013 16:39:40 %S A231969 2,10,110,2530,118910,17036047229140531, %T A231969 4713753689937227789548410467592773787730621935419, %U A231969 4754361703029497628070972207349674154455369685904736544199583856401,17434718204270642890620908753958444038404912529730635812020757976125828120134034469 %N A231969 a(n) = the smallest squarefree number (A005117) with n prime factors in a 2p+1 progression. %C A231969 Smallest squarefree numbers with n >= 2 prime divisors of the form p_1 * p_2 * … * p_n, where p_1 < p_2 < … < p_k = primes with p_k = 2 * p_(k-1) + 1. %H A231969 Jaroslav Krizek, <a href="/A231969/b231969.txt">Table of n, a(n) for n = 1..12</a> %e A231969 17036047229140531 = 89*179*359*719*1439*2879, where 179 = 2*89 + 1, 359 = 2*179 + 1, 719 = 2*359 + 1, 1439 = 2*719 + 1, 2879 = 2*1439 + 1. %Y A231969 Cf. A005117, A000040, A231966, A231967, A231968. %K A231969 nonn %O A231969 1,1 %A A231969 _Jaroslav Krizek_, Nov 16 2013