I am pretty sure I bought this on eBay but it was five years ago. I'm planning on adapting it to my Micro Four Thirds camera, and suspect it is a Minolta Rokkor.
Here is an imgur gallery with more photos: https://imgur.com/gallery/WqYyfnD
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This is a Minolta MD lens mount. It's hard to see in your photo, but by increasing the brightness, you can see the shutter-preferred auto-exposure lug (called the MD lug) (blue arrow), and the meter coupling (MC) tab (red arrow). These lugs identify it as a MD mount lens.