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 A175466 #15 Aug 14 2025 04:24:58 %S A175466 1,1,1,1,2,1,1,1,1,1,1,2,3,2,1,1,2,1,1,2,1,1,2,1,4,1,2,1,1,1,3,2,2,3, %T A175466 1,1,1,2,3,2,5,2,3,2,1,1,2,1,1,2,2,1,1,2,1,1,2,1,4,1,6,1,4,1,2,1,1,2, %U A175466 1,4,2,3,3,2,4,1,2,1,1,2,3,2,2,2,7,2,2 %N A175466 Table read by antidiagonals: a(m,n) = the largest positive integer occurring, when written in binary, as a substring in both binary m and binary n. %H A175466 Rémy Sigrist, <a href="/A175466/b175466.txt">Table of n, a(n) for n = 1..11325</a> %H A175466 Rémy Sigrist, <a href="/A175466/a175466.png">Colored representation of the table for n = 1..1023 and k = 1023</a> %F A175466 From _Rémy Sigrist_, Jul 20 2019: (Start) %F A175466 1 <= a(n, k) <= min(n, k). %F A175466 a(n, k) = a(k, n). %F A175466 a(n, n) = n. %F A175466 a(n, 1) = 1. %F A175466 a(n, 2) = A043529(n). %F A175466 a(n, 3) = 3 iff n belongs to A004780. (End) %e A175466 From _Rémy Sigrist_, Jul 20 2019: (Start) %e A175466 Table a(n, k) begins (in decimal): %e A175466 n\k| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 %e A175466 ---+--------------------------------------------------- %e A175466 1| 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 %e A175466 2| 1 2 1 2 2 2 1 2 2 2 2 2 2 2 1 %e A175466 3| 1 1 3 1 1 3 3 1 1 1 3 3 3 3 3 %e A175466 4| 1 2 1 4 2 2 1 4 4 2 2 4 2 2 1 %e A175466 5| 1 2 1 2 5 2 1 2 2 5 5 2 5 2 1 %e A175466 6| 1 2 3 2 2 6 3 2 2 2 3 6 6 6 3 %e A175466 7| 1 1 3 1 1 3 7 1 1 1 3 3 3 7 7 %e A175466 8| 1 2 1 4 2 2 1 8 4 2 2 4 2 2 1 %e A175466 9| 1 2 1 4 2 2 1 4 9 2 2 4 2 2 1 %e A175466 10| 1 2 1 2 5 2 1 2 2 10 5 2 5 2 1 %e A175466 11| 1 2 3 2 5 3 3 2 2 5 11 3 5 3 3 %e A175466 12| 1 2 3 4 2 6 3 4 4 2 3 12 6 6 3 %e A175466 13| 1 2 3 2 5 6 3 2 2 5 5 6 13 6 3 %e A175466 14| 1 2 3 2 2 6 7 2 2 2 3 6 6 14 7 %e A175466 15| 1 1 3 1 1 3 7 1 1 1 3 3 3 7 15 %e A175466 Table a(n, k) begins (in binary): %e A175466 n\k| 1 10 11 100 101 110 111 1000 1001 1010 1011 1100 1101 1110 1111 %e A175466 ----+---------------------------------------------------------------- %e A175466 1| 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 %e A175466 10| 1 10 1 10 10 10 1 10 10 10 10 10 10 10 1 %e A175466 11| 1 1 11 1 1 11 11 1 1 1 11 11 11 11 11 %e A175466 100| 1 10 1 100 10 10 1 100 100 10 10 100 10 10 1 %e A175466 101| 1 10 1 10 101 10 1 10 10 101 101 10 101 10 1 %e A175466 110| 1 10 11 10 10 110 11 10 10 10 11 110 110 110 11 %e A175466 111| 1 1 11 1 1 11 111 1 1 1 11 11 11 111 111 %e A175466 1000| 1 10 1 100 10 10 1 1000 100 10 10 100 10 10 1 %e A175466 1001| 1 10 1 100 10 10 1 100 1001 10 10 100 10 10 1 %e A175466 1010| 1 10 1 10 101 10 1 10 10 1010 101 10 101 10 1 %e A175466 1011| 1 10 11 10 101 11 11 10 10 101 1011 11 101 11 11 %e A175466 1100| 1 10 11 100 10 110 11 100 100 10 11 1100 110 110 11 %e A175466 1101| 1 10 11 10 101 110 11 10 10 101 101 110 1101 110 11 %e A175466 1110| 1 10 11 10 10 110 111 10 10 10 11 110 110 1110 111 %e A175466 1111| 1 1 11 1 1 11 111 1 1 1 11 11 11 111 1111 %e A175466 (End) %o A175466 (PARI) sub(n) = { my (b=binary(n), s=[]); for (i=1, #b, if (b[i], for (j=i, #b, s=setunion(s, Set(fromdigits(b[i..j], 2)))))); return (s) } %o A175466 T(n,k) = my (i=setintersect(sub(n), sub(k))); i[#i] \\ _Rémy Sigrist_, Jul 20 2019 %Y A175466 Cf. A043529, A004780, A175488. %K A175466 base,nonn,tabl %O A175466 1,5 %A A175466 _Leroy Quet_, May 24 2010 %E A175466 More terms from _Rémy Sigrist_, Jul 20 2019