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 A228171 #15 Aug 17 2013 17:25:15
%S A228171 2,3,7,31,89,139,113,211,1381,1637,1129,2557,2971,1327,15683,16141,
%T A228171 9973,35677,34061,43331,19609,107377,162143,44293,404597,461717,
%U A228171 838249,155921,535399,492113,396733,2181737,370261,1468277,6034247,3933599,1671781,25180171
%N A228171 Least prime such that between it and the next prime there are exactly n semiprimes.
%C A228171 a(62) = 1294268491, a(64) = 2300942549.
%H A228171 Giovanni Resta, <a href="/A228171/b228171.txt">Table of n, a(n) for n = 0..91</a>
%F A228171 a(n) is the prime precessing A228170(n-1).
%e A228171 a(2) = 7 since between 7 and the next prime, 11, there are 2 semiprimes (9, 10).
%t A228171 t = Table[0, {100}]; p=3; While[p < 3100000000, q = NextPrime[p]; a = Count[ PrimeOmega[ Range[p, q]], 2]; If[ t[[a]] == 0, t[[a]] = p; Print[{p, a}]]; p = q]; t
%Y A228171 Cf. A133478, A228170.
%K A228171 nonn
%O A228171 0,1
%A A228171 _Jack Brennen_, _Jonathan Vos Post_, _Zak Seidov_, and _Robert G. Wilson v_, Aug 14 2013