may file a certificate on Form 2031 on behalf of such individual. The certificate must be filed after July 30, 1965 (the date of enactment of the Social Security Amendments of 1965), and on or before April 17, 1967. Subject to the conditions stated in subparagraph (4) of this paragraph, such certificate shall be effective for the first taxable year ending after 1954 for which a return, as described in subparagraph (1) of this paragraph, was filed by such individual and for all succeeding taxable years.
26 C.F.R. §1.1402(e)(5)-2