Question: Who is the Artist with an Issue Price (BU) [Clarification Needed] of n/a along with  a Year larger than 2004, and Mintage (Proof) of 25,000?
SQL: SELECT artist FROM table_name_53 WHERE issue_price__bu_[_clarification_needed_] = "n/a" AND year > 2004 AND mintage__proof_ = "25,000"