This utility is provided by CAMBIA's Patent Lens Sequence Project. It uses NCBI's blast software to search sequences that are specifically listed in U.S. patents and published patent applications. The collections that can be searched using this page are (both Applications & Grants that were available on 19/Feb/08):

• US_A-aa and US_A-nt (amino acids and nucleotide sequences in published patent applications which may be pending)
• US_B-aa and US_B-nt (amino acids and nucleotide sequences in granted patents) and
• US_A-aa-inClaims, US_A-nt-inClaims, US_B-aa-inClaims and US_B-nt-inClaims, containing the subset of sequences explicitly mentioned in claims as opposed to anywhere else in the patent specifications.