cp's OEIS Frontend

A202272 Numbers n with k digits such that each sum of 1, 2, ..., k digits of n is a substring of n.

%I A202272 #13 Feb 01 2022 01:36:35
%S A202272 0,1,2,3,4,5,6,7,8,9,10,20,30,40,50,60,70,80,90,100,109,200,300,400,
%T A202272 500,600,700,800,910,1000,1009,1090,2000,3000,4000,5000,6000,7000,
%U A202272 8000,9000,9010,9100,10000,10009,10090,10900,20000,30000,40000,50000,60000,70000
%N A202272 Numbers n with k digits such that each sum of 1, 2, ..., k digits of n is a substring of n.
%C A202272 Conjecture: sequence contains only
%C A202272 - numbers of the form k*10^j (j>=0, k>=0),
%C A202272 - numbers of the form 10X, where X = string of k digits containing one digit 9 and k-1 digits 0 (k>=1),
%C A202272 - numbers of form 9Y10Z; where Y = string of k digits 0 (k>=0), Z = string of j digits 0 (j>=0).
%C A202272 Subsequence of A052018.
%e A202272 109 is a term because all possible sums of digits 0, 1, 1, 9, 9, 10 are its substrings.
%Y A202272 Cf. A052018 (numbers k such that the sum of the digits of k is substring of k).
%K A202272 nonn,base
%O A202272 1,3
%A A202272 _Jaroslav Krizek_, Jan 06 2012