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 A101421 #9 Jun 13 2020 00:51:14
%S A101421 28,35,91,126,133,189,217,224,280,539,637,686,728,756,854,945,1001,
%T A101421 1008,1064,1358,1456,1512,1547,1729,1736,1792,2198,2205,2240,2261,
%U A101421 2331,2457,2709,2926,3059,3087,3402,3500,3528,3591,4123,4221,4312,4375,4914,4921
%N A101421 Numbers which are the sum of two positive cubes and divisible by 7.
%H A101421 Vincenzo Librandi, <a href="/A101421/b101421.txt">Table of n, a(n) for n = 1..1000</a>
%t A101421 upto[n_] := Block[{t}, Union@ Reap[Do[If[Mod[t = x^3 + y^3, 7] == 0, Sow@t], {x, n^(1/3)}, {y, Min[x, (n - x^3)^(1/3)]}]][[2, 1]]]; upto[5000] (* _Giovanni Resta_, Jun 12 2020 *)
%Y A101421 Cf. A003325.
%K A101421 nonn
%O A101421 1,1
%A A101421 Jun Mizuki (suzuki32(AT)sanken.osaka-u.ac.jp), Jan 17 2005
%E A101421 Changed offset from 0 to 1 by _Vincenzo Librandi_, May 08 2013