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 A214676 #27 Feb 16 2025 08:33:18 %S A214676 1,1,11,1,2,111,1,2,11,1111,1,2,3,12,11111,1,2,3,11,21,111111,1,2,3,4, %T A214676 12,22,1111111,1,2,3,4,11,13,111,11111111,1,2,3,4,5,12,21,112, %U A214676 111111111,1,2,3,4,5,11,13,22,121,1111111111 %N A214676 A(n,k) is n represented in bijective base-k numeration; square array A(n,k), n>=1, k>=1, read by antidiagonals. %C A214676 The digit set for bijective base-k numeration is {1, 2, ..., k}. %H A214676 Alois P. Heinz, <a href="/A214676/b214676.txt">Antidiagonals n = 1..18, flattened</a> %H A214676 R. R. Forslund, <a href="http://www.emis.de/journals/SWJPAM/Vol1_1995/rrf01.ps">A logical alternative to the existing positional number system</a>, Southwest Journal of Pure and Applied Mathematics, Vol. 1, 1995, 27-29. %H A214676 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/Zerofree.html">Zerofree</a> %H A214676 Wikipedia, <a href="https://en.wikipedia.org/wiki/Bijective_numeration">Bijective numeration</a> %e A214676 Square array A(n,k) begins: %e A214676 : 1, 1, 1, 1, 1, 1, 1, 1, ... %e A214676 : 11, 2, 2, 2, 2, 2, 2, 2, ... %e A214676 : 111, 11, 3, 3, 3, 3, 3, 3, ... %e A214676 : 1111, 12, 11, 4, 4, 4, 4, 4, ... %e A214676 : 11111, 21, 12, 11, 5, 5, 5, 5, ... %e A214676 : 111111, 22, 13, 12, 11, 6, 6, 6, ... %e A214676 : 1111111, 111, 21, 13, 12, 11, 7, 7, ... %e A214676 : 11111111, 112, 22, 14, 13, 12, 11, 8, ... %p A214676 A:= proc(n, b) local d, l, m; m:= n; l:= NULL; %p A214676 while m>0 do d:= irem(m, b, 'm'); %p A214676 if d=0 then d:=b; m:=m-1 fi; %p A214676 l:= d, l %p A214676 od; parse(cat(l)) %p A214676 end: %p A214676 seq(seq(A(n, 1+d-n), n=1..d), d=1..12); %t A214676 A[n_, b_] := Module[{d, l, m}, m = n; l = Nothing; While[m > 0, {m, d} = QuotientRemainder[m, b]; If[d == 0, d = b; m--]; l = {d, l}]; FromDigits @ Flatten @ l]; %t A214676 Table[A[n, d-n+1], {d, 1, 12}, {n, 1, d}] // Flatten (* _Jean-François Alcover_, May 28 2019, from Maple *) %Y A214676 Columns k=1-9 give: A000042, A007931, A007932, A084544, A084545, A057436, A214677, A214678, A052382. %Y A214676 A(n+1,n) gives A010850. %K A214676 nonn,tabl %O A214676 1,3 %A A214676 _Alois P. Heinz_, Jul 25 2012