%I #8 Jul 13 2013 12:04:08
%S 0,1,1,1,1,2,2,2,1,1,2,2,2,2,3,3,1,2,2,2,2,3,3,3,2,1,2,2,2,2,3,3,3,2,
%T 2,3,1,2,2,2,2,3,3,3,2,2,3,3,3,1,2,2,2,2,3,3,3,2,2,3,3,3,3,4,1,2,2,2,
%U 2,3,3,3,2,2,3,3,3,3,4,4,2,1,2,2,2,2
%N Number of nonzero digits when writing n in base where place values are squares, cf. A007961.
%C For n > 0: a(A000290(n)) = 1; for n > 1: a(A002522(n)) = 2;
%C a(n) <= A000196(n).
%H Reinhard Zumkeller, <a href="/A190321/b190321.txt">Table of n, a(n) for n = 0..10000</a>
%o (Haskell)
%o a190321 n = g n $ reverse $ takeWhile (<= n) $ tail a000290_list where
%o g _ [] = 0
%o g m (x:xs) | x > m = g m xs
%o | otherwise = signum m' + g r xs where (m',r) = divMod m x
%Y Cf. A190311, A053610.
%K nonn,base
%O 0,6
%A _Reinhard Zumkeller_, May 08 2011