cp's OEIS Frontend

A330521 Lexicographically earliest sequence of distinct positive terms such that the digitsum of a(n) ends a(n+1).

%I A330521 #14 Mar 02 2020 09:23:09
%S A330521 1,11,2,12,3,13,4,14,5,15,6,16,7,17,8,18,9,19,10,21,23,25,27,29,111,
%T A330521 33,26,28,110,22,24,36,39,112,34,37,210,43,47,211,44,38,311,35,48,212,
%U A330521 45,49,113,55,310,54,59,114,46,410,65,411,56,511,57,312,66,412,67,213,76,313,77,214,87,115,97,116,58,413,68,314
%N A330521 Lexicographically earliest sequence of distinct positive terms such that the digitsum of a(n) ends a(n+1).
%C A330521 This is conjectured to be a permutation of the integers > 0.
%H A330521 Carole Dubois, <a href="/A330521/b330521.txt">Table of n, a(n) for n = 1..5000</a>
%e A330521 a(1) = 1 has digitsum 1, and this 1 ends a(2) = 11;
%e A330521 a(2) = 11 has digitsum 2 and this 2 ends a(3) = 2;
%e A330521 a(3) = 2 has digitsum 2 and this 2 ends a(4) = 12;
%e A330521 a(4) = 12 has digitsum 3 and this 3 ends a(5) = 3;
%e A330521 a(5) = 3 has digitsum 3 and this 3 ends a(6) = 13;
%e A330521 ...
%e A330521 a(18) = 19 has digitsum 10 and this 10 ends a(19) = 10;
%e A330521 a(19) = 10 has digitsum 1 and this 1 ends a(20) = 21 (as 1 and 11 are already in the sequence); etc.
%Y A330521 Cf. A248025.
%K A330521 nonn,look,base
%O A330521 1,2
%A A330521 _Carole Dubois_ and _Eric Angelini_, Mar 01 2020