Gregory's ServerI was selling Intel product at the time.
We were told the trademark determination happened during Intel's transition from x386 to x486(x86,x286,x386,x486*) so, AMD went 486 and Intel skipped 4 and went to 5, being a pentagon... hence... the trademarkable Pentium.
@avoca @kenshirriff maybe I'm misunderstanding what you said but Intel definitely *did not* skip 486 models. There was a whole line of them that preceded the Pentium. I owned and/or used several of them. They "skipped" 586 as a numbering/naming scheme and went to Pentium, but it was after years of 486 being the top of the line chip.
https://en.m.wikipedia.org/wiki/I486
Apologies if I'm simply misunderstanding you.