cp's OEIS Frontend

A333358 a(1) = 0. For n>1, a(n+1) = the minimum positive m such that the concatenation of the decimal values [a(n-m),a(n-m+1),...,a(n-m+k)] equals a(n) for some k>=0; a(n+1) = a(n) + 1 if no such m exists.

%I A333358 #5 Mar 19 2020 10:33:10
%S A333358 0,1,2,3,4,5,6,7,8,9,10,11,12,11,2,12,3,13,14,15,16,17,18,19,20,21,22,
%T A333358 23,25,26,27,28,29,30,31,32,33,34,34,1,38,39,40,41,42,43,44,45,43,3,
%U A333358 33,14,33,2,39,13,38,16,37,38,3,11,48,49,50,51,52,53,54,55,56,65,66,67,67,1,36
%N A333358 a(1) = 0. For n>1, a(n+1) = the minimum positive m such that the concatenation of the decimal values [a(n-m),a(n-m+1),...,a(n-m+k)] equals a(n) for some k>=0; a(n+1) = a(n) + 1 if no such m exists.
%e A333358 a(n) = n-1 for 2 <= n <= 13 as a(1) = 0 and no choice for a(n) equals the concatenation of one or more previous terms, so a(n) = a(n-1) + 1 = n-1.
%e A333358 a(14) = 11 as a(13) = 12, and the value '12' is the concatenation of a(2) = 1 and a(3) = 2, and a(2) is eleven terms back from a(13).
%e A333358 a(15) = 2 as a(14) = 11, and the value '11' is a(12), which is two terms back from a(14).
%Y A333358 Cf. A181391, A007908, A001704.
%K A333358 nonn,base
%O A333358 1,3
%A A333358 _Scott R. Shannon_, Mar 16 2020