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 A070764 #35 Mar 11 2019 11:42:03 %S A070764 0,0,0,0,0,0,0,0,1,4,25,108,450,1713,6267,21988,75185,251590,828408, %T A070764 2692630,8661287,27624040,87479663,275392248,862593661,2690285608, %U A070764 8359581585,25893044920,79978118632,246433568617 %N A070764 Number of polyiamonds with n cells, with holes. %H A070764 Craig Knecht, <a href="/A070764/a070764_2.png">Enneiamond with a hole - positions in a triangle.</a> %H A070764 Craig Knecht, <a href="/A070764/a070764_5.png">Hexagon tiling.</a> %H A070764 Craig Knecht, <a href="/A070764/a070764_3.png">Most equal distribution using the polyiamonds with holes.</a> %H A070764 Craig Knecht, <a href="/A070764/a070764.gif">Newton's Cradle.</a> %H A070764 Craig Knecht, <a href="/A070764/a070764_6.png">Polyiamond 12-gon.</a> %H A070764 Craig Knecht, <a href="/A070764/a070764_4.png">Tilings with fixed triangles in a frame.</a> %Y A070764 Equals A000577 - A070765. Cf. A001419, A038144. %K A070764 hard,nonn %O A070764 1,10 %A A070764 _Joseph Myers_, May 05 2002 %E A070764 More terms from _Joseph Myers_, Nov 11 2003 %E A070764 a(29)-a(30) from _Joseph Myers_, Nov 21 2010