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A202272
Numbers n with k digits such that each sum of 1, 2, ..., k digits of n is a substring of n.
2
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 109, 200, 300, 400, 500, 600, 700, 800, 910, 1000, 1009, 1090, 2000, 3000, 4000, 5000, 6000, 7000, 8000, 9000, 9010, 9100, 10000, 10009, 10090, 10900, 20000, 30000, 40000, 50000, 60000, 70000
OFFSET
1,3
COMMENTS
Conjecture: sequence contains only
- numbers of the form k*10^j (j>=0, k>=0),
- numbers of the form 10X, where X = string of k digits containing one digit 9 and k-1 digits 0 (k>=1),
- numbers of form 9Y10Z; where Y = string of k digits 0 (k>=0), Z = string of j digits 0 (j>=0).
Subsequence of A052018.
EXAMPLE
109 is a term because all possible sums of digits 0, 1, 1, 9, 9, 10 are its substrings.
CROSSREFS
Cf. A052018 (numbers k such that the sum of the digits of k is substring of k).
Sequence in context: A052018 A352461 A302768 * A180480 A080459 A093475
KEYWORD
nonn,base
AUTHOR
Jaroslav Krizek, Jan 06 2012
STATUS
approved