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 A359689 #19 Oct 28 2023 23:54:14 %S A359689 2,1,2,4,8,19,48,120,320,864,2372,6581,18470,52094,147966,421931, %T A359689 1208214,3470789,10001186,28892674,83671476,242823392,706090582, %U A359689 2056861981,6001601254,17538308071,51323923796,150389970179,441211039118,1295886198194,3810209524640,11214075937205,33035791339150 %N A359689 a(n) is the number of free polyiamonds of n cells with chessboard coloring. %H A359689 John Mason, <a href="/A359689/b359689.txt">Table of n, a(n) for n = 1..51</a> %H A359689 John Mason, <a href="/A000577/a000577_1.pdf">Counting Polyiamonds</a> %H A359689 John Mason, <a href="/A359689/a359689.jpg">Illustrations</a> %F A359689 See link "Counting Polyiamonds". %Y A359689 Cf. A000577, A001933. %K A359689 nonn %O A359689 1,1 %A A359689 _John Mason_, Jan 11 2023 %E A359689 More terms from _John Mason_, Oct 28 2023