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 A223542 #21 Apr 04 2013 14:26:11 %S A223542 0,1,1,3,2,3,5,5,5,5,9,7,4,7,9,11,11,6,6,11,11,15,13,15,8,15,13,15,19, %T A223542 19,19,19,19,19,19,19,27,23,17,23,10,23,17,23,27,29,29,21,21,12,12,21, %U A223542 21,29,29,33,31,33,25,16,14,16,25,33,31 %N A223542 Key-matrix of A223541 (nim-products of powers of 2) read by antidiagonals. %C A223542 Matrix A223541 has very large entries, which are listed in A223543. This matrix has the same pattern as A223541, but the actual entries are replaced by the index numbers of A223543. Surprisingly, although it is just a helper, the key-matrix is mathematically interesting on its own. (See the fractal patterns in the SVG files of the binary and the ternary dual matrix.) Its diagonal is A006046-1. %H A223542 Tilman Piesk, <a href="/A223542/b223542.txt">First 128 rows of the matrix, flattened</a> %H A223542 Tilman Piesk, <a href="/A223542/a223542.txt">256x256 key-matrix</a> %H A223542 Tilman Piesk, <a href="http://commons.wikimedia.org/wiki/Category:Nim-products_of_2-powers;_key_matrix;_dual">Elements of binary dual matrix</a> (13 SVGs) %H A223542 Tilman Piesk, <a href="http://commons.wikimedia.org/wiki/Category:Nim-products_of_2-powers;_key_matrix;_ternary_dual">Elements of ternary dual matrix</a> (8 SVGs) %H A223542 Tilman Piesk, <a href="http://en.wikiversity.org/wiki/Walsh_permutation;_nimber_multiplication">Walsh permutation; nimber multiplication</a> (Wikiversity) %F A223542 A223541(m,n) = A223543( a(m,n) ). %F A223542 Diagonal: a(n,n) = A006046(n+1)-1. %Y A223542 A223541, A223543, A006046 %K A223542 nonn,tabl %O A223542 0,4 %A A223542 _Tilman Piesk_, Mar 21 2013