@katliamom Very useful info you provided just above, thanks.
I went to look at Amherst’s math dept recs for potential PhDs and they recommend a sequence that includes a few UMass courses, I think 4. So that may be the sweetest spot of all - a LAC (with close prof relationships and advising and such) in a consortium with a university with advanced offerings.
In the meantime, I found a few lists.
There, 4 out of the top 10 are LACs.
Then this one (domain may be blocked by CC, not sure) - https://www.■■■■■■■■■■■■■■■■■■■■■■/infographics/top-feeders-phd-programs - that breaks down by PhD subject, same source, the NSF, but did something that made a somewhat different list. This is again math PhDs only:
and http://www.thecollegesolution.com/the-colleges-where-phds-get-their-start/ has a similar list for math ('97-'06) - same as the first.