cp's OEIS Frontend

A126968 First digit of a(n) is the a(n)-th digit of S [a(n+1) is the smallest available integer not yet present in S].

%I A126968 #21 Aug 24 2025 05:50:04
%S A126968 0,1,2,3,4,5,6,7,8,9,11,12,13,21,14,31,22,15,16,41,32,17,23,24,18,51,
%T A126968 19,61,42,111,33,25,112,71,26,34,27,43,113,81,52,114,115,91,62,116,44,
%U A126968 28,117,118,119,35,36,29,53,121,122,211,72,123,212,63,37,45
%N A126968 First digit of a(n) is the a(n)-th digit of S [a(n+1) is the smallest available integer not yet present in S].
%C A126968 An example of what logologists call a "self-acronymic" sequence.
%C A126968 Except for the initial term, the sequence consists only of zeroless numbers A052382, since no other term can start with a digit 0. - _M. F. Hasler_, Jan 19 2015
%H A126968 Hans Havermann, <a href="/A126968/b126968.txt">Table of n, a(n) for n = 0..10000</a>
%e A126968 The first integer of S starts with the first digit of S: 0,
%e A126968 the second integer of S starts with the second digit of S: 1,
%e A126968 the third integer of S starts with the third digit of S: 2,
%e A126968 the fourth integer of S starts with the fourth digit of S: 3,
%e A126968 the fifth integer of S starts with the fifth digit of S: 4,
%e A126968 the sixth integer of S starts with the sixth digit of S: 5,
%e A126968 the 7th integer of S starts with the 7th digit of S: 6,
%e A126968 ...
%e A126968 the 11th integer of S ("11") starts with the 11th dig. of S : 1,
%e A126968 the 12th integer of S ("12") starts with the 12th dig. of S : 1,
%e A126968 the 13th integer of S ("13") starts with the 13th dig. of S : 1,
%e A126968 the 14th integer of S ("21") starts with the 14th dig. of S : 2, ...
%Y A126968 Cf. A126969.
%K A126968 nonn,base,changed
%O A126968 0,3
%A A126968 _Eric Angelini_, Mar 22 2007
%E A126968 Corrected and edited by _Eric Angelini_, Dec 05 2011
%E A126968 Corrected and extended by _Hans Havermann_, Jan 19 2015