

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
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OFFSET

3,1


COMMENTS

Will every term be between 28 and 31 inclusive?


REFERENCES

Jason Earls, Red Zen, Lulu Press, NY, 2006, pp. 145146. ISBN: 9781430320173.


LINKS

Amiram Eldar, Table of n, a(n) for n = 3..10000


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 A295749 A022399
Adjacent sequences: A129284 A129285 A129286 * A129288 A129289 A129290


KEYWORD

nonn,base


AUTHOR

Jason Earls, May 26 2007


STATUS

approved



