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 A004979 #10 Feb 19 2019 03:56:52 %S A004979 1,3,4,8,14,22,31,43,58,74,94,116,140,165,191,223,256,290,327,365,406, %T A004979 451,498,546,599,655,714,775,837,901,969,1038,1112,1188,1265,1343, %U A004979 1424,1508,1595,1683,1772,1868,1966,2066,2169,2274 %N A004979 a(n)=least number m such that m-a(n-1)<>a(j)-a(k) for all j,k less than m; a(1)=1, a(2)=3. %Y A004979 Cf. A048212, A048216, A048217. %K A004979 nonn %O A004979 1,2 %A A004979 _Clark Kimberling_