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 A217851 #8 Dec 27 2012 12:02:25 %S A217851 6,9,14,21,33,106,611,1437,2701,6583,16078,17993,32807,35135,36019, %T A217851 340941,1069595,1589717,3586913,5835265,139139963,251306399,285074774, %U A217851 327023293,751412039,981270997,2655397729,5238281053,6498130471,8512915685,16328958739 %N A217851 Least semiprime m such that the previous semiprime is m - A215231(n). %C A217851 These are the semiprimes that are the upper end of the gaps of length A215231. The lower end semiprimes are given in A215232. %H A217851 Donovan Johnson, <a href="/A217851/b217851.txt">Table of n, a(n) for n = 1..38</a> %Y A217851 Cf. A001358 (semiprimes), A131109, A215231, A215232. %K A217851 nonn,hard %O A217851 1,1 %A A217851 _T. D. Noe_, Nov 07 2012