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 A240600 #15 May 12 2014 11:52:10 %S A240600 0,1,1,2,2,4,3,3,3,5,4,5,5,7,5,5,5,6,6,8,6,8,7,7,7,9,7,7,7,9,8,9,9,11, %T A240600 9,11,9,9,9,11,9,10,10,12,10,12,12,14,12,14,13,13,11,11,11,13,13,15, %U A240600 13,13,13,15,14 %N A240600 Number of partially filled hexagons in the first 120-degree circular sector of hexagonal lattice A_2 centered at deep hole along the edge of a circle also centered at the deep hole. %C A240600 A(n) alternates between the numbers for circles which intersect points on the A2 lattice and the numbers for circles which pass in between the points on a lattice. %H A240600 Rajan Murthy, <a href="/A240600/a240600.txt">Code for computing 3*A(n) as a function of R^2 (scilab)</a> %e A240600 for n = 1, the squared radius is in the open interval (0,1) and the corresponding circle passes through 1 hexagon. %e A240600 for n = 14, the squared radius is 13 with the corresponding circle passing through the furthest corner of 2 hexagons and passing through 5 hexagons. %Y A240600 A038588 gives the number of hexagons completely encircled in all three circular sectors. %Y A240600 Squared radii of alternate entries is given by the Loeschian numbers A003136. %Y A240600 A234300 is the analog for the 2-d Cartesian lattice. %Y A240600 A237708 is the analog for the 3-d Cartesian lattice. %Y A240600 A239353 is the analog for the 4-d Cartesian lattice. %K A240600 nonn %O A240600 0,4 %A A240600 _Rajan Murthy_, Apr 09 2014