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 A251559 #16 May 09 2021 02:19:51 %S A251559 9,9,9,9,15,15,21,21,21,21,21,21,39,39,39,39,39,39,39,39,45,45,45,45, %T A251559 45,49,49,55,55,55,55,55,55,57,57,69,69,93,93,93,93,93,93,93,93,93,93, %U A251559 93,93,93,93,93,93,93,93,93,93,93,93,93,93,93,93,99,99,105,105,105,105,121 %N A251559 a(n) = 2 more than the largest odd number among {A098550(1), A098550(2), ..., A098550(n)} which is neither a prime nor a term of A251542. %H A251559 David L. Applegate, Hans Havermann, Bob Selcoe, Vladimir Shevelev, N. J. A. Sloane, and Reinhard Zumkeller, <a href="http://arxiv.org/abs/1501.01669">The Yellowstone Permutation</a>, arXiv preprint arXiv:1501.01669 [math.NT], 2015 and <a href="https://cs.uwaterloo.ca/journals/JIS/VOL18/Sloane/sloane9.html">J. Int. Seq. 18 (2015) 15.6.7</a>. %Y A251559 Cf. A098550, A251546, A251557, A251558. %K A251559 nonn %O A251559 1,1 %A A251559 _N. J. A. Sloane_, Dec 23 2014