Return the base-2 representation of positive integer n as a string.
abjad> mathtools.binary_string(5)
'101'
abjad> for n in range(1, 17):
... print '\t%s\t%s' % (n, mathtools.binary_string(n))
...
1 1
2 10
3 11
4 100
5 101
6 110
7 111
8 1000
9 1001
10 1010
11 1011
12 1100
13 1101
14 1110
15 1111
16 10000
Note
mathtools.binary_string(n) will deprecate when Abjad migrates to Python 2.6.