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A214677 a(n) = n represented in bijective base-7 numeration.

%I A214677 #22 Feb 16 2025 08:33:18
%S A214677 1,2,3,4,5,6,7,11,12,13,14,15,16,17,21,22,23,24,25,26,27,31,32,33,34,
%T A214677 35,36,37,41,42,43,44,45,46,47,51,52,53,54,55,56,57,61,62,63,64,65,66,
%U A214677 67,71,72,73,74,75,76,77,111,112,113,114,115,116,117,121,122
%N A214677 a(n) = n represented in bijective base-7 numeration.
%H A214677 Alois P. Heinz, <a href="/A214677/b214677.txt">Table of n, a(n) for n = 1..10000</a>
%H A214677 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 A214677 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/Zerofree.html">Zerofree</a>
%H A214677 Wikipedia, <a href="https://en.wikipedia.org/wiki/Bijective_numeration">Bijective numeration</a>
%p A214677 a:= proc(n) local d, l, m; m:= n; l:= NULL;
%p A214677       while m>0 do d:= irem(m, 7, 'm');
%p A214677         if d=0 then d:=7; m:= m-1 fi;
%p A214677         l:= d, l
%p A214677       od; parse(cat(l))
%p A214677     end:
%p A214677 seq(a(n), n=1..100);
%t A214677 With[{b = 7}, Flatten@ Table[FromDigits[PadLeft[IntegerDigits[k, b], n] /. k_ :> k + 1], {n, 3}, {k, 0, b^n - 1}] ] (* _Michael De Vlieger_, Sep 16 2023 *)
%Y A214677 Column k=7 of A214676.
%K A214677 nonn,base,easy
%O A214677 1,2
%A A214677 _Alois P. Heinz_, Jul 25 2012