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 A363930 #9 Jun 30 2023 01:01:40 %S A363930 0,0,1,0,2,0,3,0,1,3,4,0,1,4,5,0,6,0,7,0,1,7,8,0,1,2,3,6,7,8,9,0,2,3, %T A363930 7,8,10,0,3,8,11,0,1,3,9,11,12,0,1,12,13,0,14,0,15,0,1,15,16,0,1,2,3, %U A363930 14,15,16,17,0,2,3,4,6,12,14,15,16,18,0,3,4,7,12,15,16,19 %N A363930 Irregular table T(n, k), n >= 0, k = 1..A363710(n), read by rows; the n-th row lists the nonnegative numbers m <= n such that A003188(m) AND A003188(n-m) = 0 (where AND denotes the bitwise AND operator). %C A363930 This sequence is related to the T-square fractal (see A363710). %H A363930 Rémy Sigrist, <a href="/A363930/b363930.txt">Table of n, a(n) for n = 0..13126</a> (rows for n = 0..2^9 flattened) %H A363930 Wikipedia, <a href="https://en.wikipedia.org/wiki/T-square_(fractal)">T-square (fractal)</a> %F A363930 T(n, 1) = 0. %F A363930 T(n, A363710(n)) = n. %F A363930 T(n, k) + T(n, A363710(n)+1-k) = n. %e A363930 Table T(n, k) begins: %e A363930 n n-th row %e A363930 -- ---------------------- %e A363930 0 0 %e A363930 1 0, 1 %e A363930 2 0, 2 %e A363930 3 0, 3 %e A363930 4 0, 1, 3, 4 %e A363930 5 0, 1, 4, 5 %e A363930 6 0, 6 %e A363930 7 0, 7 %e A363930 8 0, 1, 7, 8 %e A363930 9 0, 1, 2, 3, 6, 7, 8, 9 %e A363930 10 0, 2, 3, 7, 8, 10 %e A363930 11 0, 3, 8, 11 %e A363930 12 0, 1, 3, 9, 11, 12 %e A363930 13 0, 1, 12, 13 %e A363930 14 0, 14 %e A363930 15 0, 15 %e A363930 16 0, 1, 15, 16 %o A363930 (PARI) row(n) = { select (m -> bitand(bitxor(m, m\2), bitxor(n-m, (n-m)\2))==0, [0..n]) } %Y A363930 See A295989, A353174 and A362327 for similar sequences. %Y A363930 Cf. A003188, A363710. %K A363930 nonn,base,tabf %O A363930 0,5 %A A363930 _Rémy Sigrist_, Jun 28 2023