Perhaps it is due to me getting older, but these days when I see PS or PS1, I think Phantasy Star I. Same goes with PS2, PS3, and PS4 being Phantasy Star II, III, and IV... especially PS4. Mayhaps that's due to myself only really playing through the active years of the PlayStation and not those of the PS2 (got it late, and it could only play CD's), PS3 (got one but I don't know if it works), and PS4 (don't have one), but that's how it is. What about you guys?
...now that I think about it, it doesn't work with PSP being Phantasy Star Portable though. To me, the PSP is the PlayStation Portable. I would like to pick up copies of Phantasy Star Portable and Phantasy Star Portable 2 though.