Our group has searched high and low for confirmation of this commonly held belief, and found nothing so far, other than the first three numbers which denote the State of issue are the same. Have you found anything further that shows the numbers are the SAME?
There are data bases commonly used by private detectives in the United States on which one can do a reverse Social Security number trace. (Input a Social Security number, and out comes the name and addresses of the individual or (in the rare case of an irregularity) individuals to whom that number was assigned.) The identity of the deceased individual previously assigned the SSN used by Obama has been explicitly mentioned on FR. He was a man born in 1890 and who died around 1980, IIRC. Orly Taitz and Susan Daniels are among those who have publicly stated the name of that individual. Since the Social Security Administration has a strict policy of never re-issuing a number already assigned, it is presumed that the Connecticut SSN used by Obama was never legally issued to him.