OFFSET
1,2
COMMENTS
Numbers of the form (10^i - 10^j)/9 with i > j.
LINKS
Robert Israel, Table of n, a(n) for n = 1..10011
FORMULA
a(i*(i-1)/2 + j) = (10^i - 10^(i-j))/9 for 1<=j<=i. - Robert Israel, Aug 16 2019
EXAMPLE
11100 = 10^2 + 10^3 + 10^4, so 11100 is in the sequence.
MAPLE
seq(seq((10^i-10^(i-j))/9, j=1..i), i=1..10); # Robert Israel, Aug 16 2019
CROSSREFS
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, Aug 15 2019
STATUS
approved