%I #10 Jan 27 2021 05:35:24
%S 29,30,31,29,30,28,29,30,30,29,28,28,29,30,30,29,29,28,30,30,31,29,29,
%T 28,29,30,30,29,28,28,29,30,31,29,29,28,30,30,30,29,29,28,29,30,30,29,
%U 28,28,30,30,31,29,29,28,29,30,30,29,29,28,29,30,30,29,29,28,30,30,31
%N Number of Harshad numbers between 10^n and 10^n + 100.
%C Will every term be between 28 and 31 inclusive?
%D Jason Earls, Red Zen, Lulu Press, NY, 2006, pp. 145-146. ISBN: 978-1-4303-2017-3.
%H Amiram Eldar, <a href="/A129287/b129287.txt">Table of n, a(n) for n = 3..10000</a>
%e There are exactly 29 Harshad numbers between 1000 and 1100, so the first term is 29.
%t a[n_] := Count[Range[10^n, 10^n + 100], _?(Divisible[#, Plus @@ IntegerDigits[#]] &)]; Array[a, 70, 3] (* _Amiram Eldar_, Jan 27 2021 *)
%Y Cf. A005349.
%K nonn,base
%O 3,1
%A _Jason Earls_, May 26 2007