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A129287
Number of Harshad numbers between 10^n and 10^n + 100.
1
29, 30, 31, 29, 30, 28, 29, 30, 30, 29, 28, 28, 29, 30, 30, 29, 29, 28, 30, 30, 31, 29, 29, 28, 29, 30, 30, 29, 28, 28, 29, 30, 31, 29, 29, 28, 30, 30, 30, 29, 29, 28, 29, 30, 30, 29, 28, 28, 30, 30, 31, 29, 29, 28, 29, 30, 30, 29, 29, 28, 29, 30, 30, 29, 29, 28, 30, 30, 31
OFFSET
3,1
COMMENTS
Will every term be between 28 and 31 inclusive?
REFERENCES
Jason Earls, Red Zen, Lulu Press, NY, 2006, pp. 145-146. ISBN: 978-1-4303-2017-3.
LINKS
EXAMPLE
There are exactly 29 Harshad numbers between 1000 and 1100, so the first term is 29.
MATHEMATICA
a[n_] := Count[Range[10^n, 10^n + 100], _?(Divisible[#, Plus @@ IntegerDigits[#]] &)]; Array[a, 70, 3] (* Amiram Eldar, Jan 27 2021 *)
CROSSREFS
Cf. A005349.
Sequence in context: A210267 A210309 A165850 * A007642 A353004 A295749
KEYWORD
nonn,base
AUTHOR
Jason Earls, May 26 2007
STATUS
approved