I'm accustomed to getting requests for WordPress files, even though I don't use WP and never have. This is common behavior from potential hackers looking for a way in. What surprises me is these requests coming from an Inktomi range:
74.6.53.180 - - [08/May/2014:23:45:12 -0700] "GET /wp-admin/ HTTP/1.1" 403 491 "-" "-"
74.6.53.180 - - [08/May/2014:23:53:54 -0700] "GET /wordpress/wp-admin/ HTTP/1.1" 403 511 "-" "-"
74.6.53.180 - - [09/May/2014:00:02:37 -0700] "GET /blog/wp-admin/ HTTP/1.1" 403 501 "-" "-"