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 A225231 #25 Nov 07 2015 17:35:50
%S A225231 9,16,23,37,53,71,93,119,147,177,211,249,289,331,377,427,479,533,591,
%T A225231 653,717,783,853,927,1003,1081,1163,1249,1337,1427,1521,1619,1719,
%U A225231 1821,1927,2037,2149,2263,2381,2503,2627,2753,2883,3017,3153,3291,3433
%N A225231 Schur numbers S(3,n).
%C A225231 a(n) is, by definition, the least positive m such that if {1,...,m} is written as a disjoint union of sets A and B, then either A contains 3 distinct numbers, one the sum of the other two, or B contains n distinct numbers, one the sum of the other n - 1.
%H A225231 Eric M. Schmidt, <a href="/A225231/b225231.txt">Table of n, a(n) for n = 3..1000</a>
%H A225231 Tanbir Ahmed, Michael G. Eldredge, Jonathan J. Marler, and Hunter S. Snevily, <a href="http://www.emis.de/journals/INTEGERS/papers/n22/n22.Abstract.html">Strict Schur Numbers</a>, INTEGERS, Electronic J. of Combinatorial Number Theory, Vol. 13, Paper A22, 2013.
%H A225231 <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (3,-4,4,-3,1).
%F A225231 For n >= 5, a(n) = 3n^2/2 - 7n/2 + c, where c = 3 if n == 0,1 (mod 4), else c = 4.
%F A225231 G.f.: x^3*(3*x^6-7*x^5+3*x^4+4*x^3-11*x^2+11*x-9) / ((x-1)^3*(x^2+1)). - _Colin Barker_, May 16 2013
%t A225231 Join[{9,16},LinearRecurrence[{3,-4,4,-3,1},{23,37,53,71,93},45]] (* _Ray Chandler_, Feb 13 2014 *)
%o A225231 (Sage) def A225231(n) : return 9 if n == 3 else 16 if n == 4 else (3*n^2 - 7*n)//2 + [3,3,4,4][n%4]
%Y A225231 Cf. A030126, A045652, A072842.
%K A225231 nonn,easy
%O A225231 3,1
%A A225231 _Eric M. Schmidt_, May 03 2013