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 A071611 #15 Aug 14 2021 15:39:44 %S A071611 6,12,24,30,48,72,96,120,144,168,192,240,264,312,336,384,408,432,480, %T A071611 504,528,552,576,600,672,696,720,768,816,864,936,1008,1032,1056,1104, %U A071611 1200,1248,1296,1344,1440,1512,1584,1680,1704,1752,1848,1920,2016 %N A071611 Number of points (i,j,k) on the surface of a sphere around (0,0,0) with squared radius A071609(n). %C A071611 a(n) is the number of lattice points on a sphere around (0,0,0) with r^2 = A071609(n). %H A071611 Hugo Pfoertner, <a href="/A071611/b071611.txt">Table of n, a(n) for n = 1..189</a> %F A071611 a(n) = A005875(A071609(n)). - _Daniel Suteu_, Aug 13 2021 %e A071611 A sphere with radius 1 has 6 lattice points on its surface, so a(1)=6. A sphere with r=sqrt(2) passes through 12 lattice points of the shape (1,1,0), so a(2)=12. A sphere with r=sqrt(5) passes through 24 lattice points with shape (2,1,0), so a(3)=24. A sphere with r=sqrt(9) passes through 6 lattice points of shape (3,0,0) and through 24 lattice points of shape (2,2,1), so a(4)=6+24=30. %Y A071611 Cf. A005875, A071342-A071344, A071609, A071610. %K A071611 nonn %O A071611 1,1 %A A071611 _Hugo Pfoertner_, May 25 2002