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 A244147 #8 Feb 27 2025 11:06:07 %S A244147 3,9,12,15,21,24,27,39,42,39,51,54,51,63,66,69,81,78,75,99,96,93,105, %T A244147 114,105,123,120,117,141,138,129,147,156,153,159,162,159,177,180,171, %U A244147 201,192,183,201,204,201,219,216,207,237,240,225,249,258,243,267,246,261,285,276 %N A244147 Number of hexagons (side length 1) that intersect the circumference of a circle of radius n centered at a lattice point. %C A244147 The pattern repeats itself at every 2*Pi/3 sector along the circumference. The hexagon count per one-third sector by rows can be arranged as an irregular triangle. The double hexagons in a row are symmetrically placed. See illustration. %H A244147 Kival Ngaokrajang, <a href="/A244147/a244147.pdf">Illustration of initial terms</a> %H A244147 Kival Ngaokrajang, <a href="/A244147/a244147.txt">Small Basic program</a> %o A244147 (Small Basic) ' See links. %Y A244147 Cf. A242118, A242394, A242395. %K A244147 nonn %O A244147 1,1 %A A244147 _Kival Ngaokrajang_, Jun 21 2014