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 A271826 #18 Apr 19 2016 16:26:37 %S A271826 6,9,15,27,48,53,59,71,72,78,84,87,90,96,98,100,116,120,121,125,134, %T A271826 153,162,163,167,180,188,204,213,215,216,224,225,226,230,240,242,243, %U A271826 244,251,253,255,262,264,279,280,287,288,289,303,314,324,330,342 %N A271826 Integers n such that n^2 = x^3 + y^3 + z^3, where x, y, z are positive integers, is soluble. %C A271826 Intersection of A000290 and A003072. %C A271826 Corresponding squares are 36, 81, 225, 729, 2304, 2809, 3481, 5041, ... %C A271826 A165454 is a subsequence. %C A271826 Terms that are not listed in A165454 are 9, 72, 100, 215, 243, 279, 289, ... %e A271826 6 is a term because 6^2 = 1^3 + 2^3 + 3^3. %e A271826 9 is a term because 9^2 = 3^3 + 3^3 + 3^3. %e A271826 15 is a term because 15^2 = 1^3 + 2^3 + 6^3. %o A271826 (PARI) list(lim) = my(v=List(), k, t); lim\=1; for(x=1, sqrtnint(lim-2, 3), for(y=1, min(sqrtnint(lim-x^3-1, 3), x), k=x^3+y^3; for(z=1, min(sqrtnint(lim-k, 3), y), if(issquare(k+z^3), listput(v, round(sqrt(k+z^3))))))); Set(v); %Y A271826 Cf. A000290, A003072, A112474, A165454. %K A271826 nonn,easy %O A271826 1,1 %A A271826 _Altug Alkan_, Apr 15 2016