I think Google is expected to abide DMCA takedowns in such cases, but IANAL. My understanding is that even an indirect reference (such as a link or infohash) is a DMCA violation.

They happily link to a prime number that will decrypt DVDs in blatant disregard for the DMCA, however. I don't believe they received a takedown request for this one.

https://www.theregister.com/2001/09/11/worlds_first_decss_ex...