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 A384430 #26 Jun 20 2025 23:10:25
%S A384430 8,9,10,13,74,23,40,88,31,22,17,56
%N A384430 a(n) is the smallest positive integer k such that the Diophantine equation x^3 + y^3 + z^3 + w^3 = k^5, where 0 < x < y < z < w has exactly n integer solutions.
%C A384430 a(13)>360.
%e A384430 a(3)=10, because 10^5 = 6^3 + 24^3 + 34^3 + 36^3 = 12^3 + 16^3 + 34^3 + 38^3 = 10^3 + 20^3 + 30^3 + 40^3 and no integer less than 10 has 3 solutions.
%t A384430 s=Table[{k, Length@Select[PowersRepresentations[k^5, 4, 3], 0<#[[1]]<#[[2]]<#[[3]]<#[[4]]&]}, {k, 20}]; a=Table[SelectFirst[s, #[[2]]==k&], {k, 4}][[All, 1]]
%Y A384430 Cf. A383877, A384182.
%K A384430 nonn,more
%O A384430 1,1
%A A384430 _Zhining Yang_, Jun 14 2025