urls of the form /:1:152 inthe 404 file

[Matt_T_hat]

My hosting 404 has logged some verystrange page requests

they take the form:

/:1:156
/:1:173
/:1:169
/:1:162
/:1:152

they have shown up on a number of domains and have just one hit each.

Some one was looking for something but can any one tell me what they were looking for?