The method of nomination for all candidates for city elections shall be by petitions. Such petitions for each candidate shall be signed by not less than fifteen registered electors of the city. No person shall sign his name to a greater number of petitions for any one office than there are persons to be elected to said office at the following regular city election. Where the signature of any individual appears on more petitions than he is permitted to sign, the signatures bearing the most recent date shall be invalidated. Nomination petitions shall be filed with the clerk up to 4:00 p.m. eastern standard time of the first Tuesday following the first Monday in August of the odd numbered years. The clerk shall publish notice of the last day permitted for filing nomination petitions and of the number of persons to be elected to each office at least one week and not more than three weeks before such last day.