

A033093


Number of 0's when n is written in base b for 2<=b<=n+1.


15



0, 1, 1, 3, 2, 3, 1, 5, 5, 5, 3, 6, 2, 3, 3, 8, 5, 9, 5, 8, 5, 4, 2, 9, 5, 5, 7, 9, 5, 8, 2, 11, 9, 8, 8, 13, 6, 7, 6, 11, 5, 9, 3, 7, 8, 5, 3, 13, 7, 10, 8, 9, 5, 12, 7, 11, 6, 5, 3, 13, 3, 4, 6, 15, 12, 14, 8, 11, 9, 12, 6, 18, 8, 9, 11, 11, 9, 11, 5, 14, 13
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

1,4


LINKS



FORMULA

Conjecture: lim inf a(n) = infinity. The lim inf grows quite slowly: e.g. a(2047)=7. Weaker conjecture: 2, 3 and 7 are the only n for which a(n) = 1. Note that a(n)=1 implies n=2 or n=2^k1; probabilistically, the chance that 2^k1 has no zeros just in base 3 is C^k, where C = (2/3)^(log(2)/log(3)) ~ .774, so the number of exceptions should be finite. It appears that 2^151 is the last n with no zeros in either base 2 or 3 (and it does have zeros in base 5).  Franklin T. AdamsWatters, Nov 07 2005


MATHEMATICA

f[n_] := Count[Flatten@ Table[ IntegerDigits[n, b], {b, 2, n + 1}], 0]; Array[f, 90] (* Robert G. Wilson v, Nov 14 2012 *)


CROSSREFS



KEYWORD

nonn,base


AUTHOR



STATUS

approved



