Strict partitions of a positive integer OEIS A000009 counts the number of strict partitions of the integers. A strict partition of a nonnegative integer n is a set of positive integers (so no repetition is allowed, and order does not matter) that sum to n.

For example, 5 has three strict partitions: 5, 4,1, and 3,2.

10 has ten partitions:

10
9,1
8,2
7,3
6,4
7,2,1
6,3,1
5,4,1
5,3,2
4,3,2,1


Challenge

Given a nonnegative integer n&lt;1000, output the number of strict partitions it has.

Test cases:

0 -&gt; 1

42 -&gt; 1426


Here is a list of the strict partition numbers from 0 to 55, from OEIS:

[1,1,1,2,2,3,4,5,6,8,10,12,15,18,22,27,32,38,46,54,64,76,89,104,122,142,165,192,222,256,296,340,390,448,512,585,668,760,864,982,1113,1260,1426,1610,1816,2048,2304,2590,2910,3264,3658,4097,4582,5120,5718,6378]


This is code-golf, so the shortest solution in bytes wins.
Pyth, 7 bytes
l{I#./Q

Try it online. Test suite.

Take the input (Q).
Find its partitions (./).
Filter it (#) on uniquify ({) not changing (I) the partition. This removes partitions with duplicates.
Find the result's length (l).