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 A248813 #50 Apr 23 2018 10:18:38 %S A248813 0,0,1,0,2,2,0,3,1,3,0,4,2,6,4,0,5,3,1,8,5,0,6,4,2,12,7,6,0,7,5,3,1, %T A248813 15,3,7,0,8,6,4,2,20,14,5,8,0,9,7,5,3,1,24,13,4,9,0,10,8,6,4,2,30,23, %U A248813 8,18,10,0,11,9,7,5,3,1,35,22,11,20,11,0,12,10,8,6,4,2,42,34,21,10,19,12 %N A248813 A(n,k) is the base-k complement of n; square array A(n,k), n>=0, k>=2, read by antidiagonals. %C A248813 Every column is a permutation of the nonnegative integers. %H A248813 Alois P. Heinz, <a href="/A248813/b248813.txt">Antidiagonals n = 0..140, flattened</a> %H A248813 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the nonnegative integers</a> %e A248813 Square array A(n,k) begins: %e A248813 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, ... %e A248813 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, ... %e A248813 2, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, ... %e A248813 3, 6, 1, 2, 3, 4, 5, 6, 7, 8, 9, ... %e A248813 4, 8, 12, 1, 2, 3, 4, 5, 6, 7, 8, ... %e A248813 5, 7, 15, 20, 1, 2, 3, 4, 5, 6, 7, ... %e A248813 6, 3, 14, 24, 30, 1, 2, 3, 4, 5, 6, ... %e A248813 7, 5, 13, 23, 35, 42, 1, 2, 3, 4, 5, ... %e A248813 8, 4, 8, 22, 34, 48, 56, 1, 2, 3, 4, ... %e A248813 9, 18, 11, 21, 33, 47, 63, 72, 1, 2, 3, ... %e A248813 10, 20, 10, 15, 32, 46, 62, 80, 90, 1, 2, ... %p A248813 A:= proc(n, k) local t, r, i; t, r:= n, 0; %p A248813 for i from 0 while t>0 do %p A248813 r:= r+k^i *irem(k-irem(t, k, 't'), k) %p A248813 od; r %p A248813 end: %p A248813 seq(seq(A(n, 2+d-n), n=0..d), d=0..14); %o A248813 (PARI) A(n,k)=fromdigits(apply(d->(k-d)%k, digits(n, k)), k); \\ _Gheorghe Coserea_, Apr 23 2018 %Y A248813 Columns k=2-16 give: A001477, A004488, A048647, A055115, A055116, A055117, A055118, A055119, A055120, A055121, A055122, A055123, A055124, A055125, A055126. %K A248813 nonn,tabl,base,look %O A248813 0,5 %A A248813 _Alois P. Heinz_, Mar 03 2015