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 A210635 #45 Jun 17 2023 22:54:57 %S A210635 0,1,1,2,0,2,3,1,3,3,4,2,0,2,4,5,3,1,5,5,5,6,4,2,0,4,4,6,7,5,3,1,7,3, %T A210635 7,7,8,6,4,2,0,6,8,6,8,9,7,5,3,1,9,5,7,9,9,10,8,6,4,2,0,8,4,6,8,10,11, %U A210635 9,7,5,3,1,11,7,11,11,11,11,12,10,8,6,4,2,0,10,6,10,10,10,12 %N A210635 Array read by descending antidiagonals: a(n,w) = ((w - (n mod w) - 1) + n) - (n mod w), n >= 0, w >= 1. %C A210635 Each column is a permutation of the nonnegative integers. %C A210635 Column w can be used to mirror horizontally an infinite rectangular image of width w stored in a array of pixels. The pixels in the first row of the image are numbered from 0 to w-1 and subsequent rows continue the numbering likewise. %F A210635 a(n,w) = ((w - (n mod w) - 1) + n) - (n mod w). %e A210635 The transposed array begins: %e A210635 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 ... %e A210635 1 0 3 2 5 4 7 6 9 8 11 10 13 12 15 14 17 16 19 18 ... %e A210635 2 1 0 5 4 3 8 7 6 11 10 9 14 13 12 17 16 15 20 19 ... %e A210635 3 2 1 0 7 6 5 4 11 10 9 8 15 14 13 12 19 18 17 16 ... %e A210635 4 3 2 1 0 9 8 7 6 5 14 13 12 11 10 19 18 17 16 15 ... %e A210635 5 4 3 2 1 0 11 10 9 8 7 6 17 16 15 14 13 12 23 22 ... %e A210635 6 5 4 3 2 1 0 13 12 11 10 9 8 7 20 19 18 17 16 15 ... %e A210635 7 6 5 4 3 2 1 0 15 14 13 12 11 10 9 8 23 22 21 20 ... %e A210635 8 7 6 5 4 3 2 1 0 17 16 15 14 13 12 11 10 9 26 25 ... %e A210635 9 8 7 6 5 4 3 2 1 0 19 18 17 16 15 14 13 12 11 10 ...... %p A210635 a:= (n,w) -> ((w - (n mod w) - 1) + n) - (n mod w): %p A210635 seq(seq(a(n,1+d-n), n=0..d), d=0..12); # _Alois P. Heinz_, Jun 07 2023 %o A210635 (PARI) a(n,w) = ((w - n % w - 1) + n) - n % w; %o A210635 matrix(7, 7, n, k, a(k-1, n)) \\ _Michel Marcus_, Jun 07 2023 %Y A210635 Column 2: A004442, column 3: A330396, column 4: A004444, column 8: A004448. %K A210635 nonn,easy,tabl %O A210635 0,4 %A A210635 _Lucas Beristayn_, Mar 25 2012 %E A210635 Edited by _N. J. A. Sloane_, Mar 26 2012 %E A210635 Entry revised by Editors of the OEIS, Jun 17 2023