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 A122872 #3 Mar 30 2012 17:35:16 %S A122872 1,2,2,3,4,3,4,5,6,4,5,8,7,8,5,6,9,12,9,10,6,7,10,13,16,11,12,7,8,11, %T A122872 14,17,20,13,14,8,9,16,15,18,21,24,15,16,9,10,17,24,19,22,25,28,17,18, %U A122872 10,11,18,25,32,23,26,29,32,19,20,11,12,19,26,33,40,27,30,33,36,21,22,12 %N A122872 Table by antidiagonals, T(n,k) is k-th number that starts with n in binary representation. %C A122872 In rows n through 2n-1, every integer >= n occurs exactly once. %F A122872 T(n,1) = n; T(n,2k) = 2T(n,k); T(n,2k+1) = 2T(n,k) + 1. T(n,k) = k + (n-1) * 2^floor(log_2(k)) = k + (n-1)*A053644(k). %e A122872 Top left corner is: %e A122872 1 2 3 4 5 %e A122872 2 4 5 8 9 %e A122872 3 6 7 12 13 %e A122872 4 8 9 16 17 %e A122872 5 10 11 20 21 %Y A122872 Rows: A000027, A004754, A004755, A004756, A004757, A004758, A004759. Algebraically, A053645 would be row zero, minus A080079 would be row minus one. See also A053644. %K A122872 easy,nonn,tabl %O A122872 1,2 %A A122872 _Franklin T. Adams-Watters_, Oct 23 2006