%I #19 Jan 02 2023 12:30:54
%S 1,2,4,80,8,81,9,10,100,90,11,12,3,31,110,91,13,40,14,5,7,41,42,30,15,
%T 6,60,92,32,33,61,51,16,70,43,82,93,71,20,44,62,52,21,22,72,83,94,400,
%U 95,73,63,50,34,77,17,84,96,74,53,98,18,85,97,49,19,700,99,68,101,23,54,45,900
%N Write under each comma the absolute difference of the two digits framing the said comma; the successive results reproduce, digit by digit, the sequence itself. This is the lexicographically earliest permutation of the positive integers with this property.
%H Carole Dubois, <a href="/A334336/b334336.txt">Table of n, a(n) for n = 1..5000</a>
%H Eric Angelini, <a href="http://list.seqfan.eu/oldermail/seqfan/2020-March/020570.html">Comma differences</a>, message to the SeqFan mailing list, March 22 2020.
%e Compare the start of the sequence and the absolute comma-differences:
%e Seq = 1, 2, 4, 80, 8, 81, 9, 10, 100, 90, 11, 12, 3, 31, 110, 91, ...
%e Dif = .1..2..4...8..0...8..8...1....9...1...0...1..0...0....9...
%e We see that the digits of the second line reproduce the digits' succession of the first line.
%Y Cf. A100787.
%K base,nonn
%O 1,2
%A _Eric Angelini_ and _Carole Dubois_, Apr 23 2020