Here. Article 2, paragraph 1: "A foreign child of less than 5 years age who is adopted by a citizen of the Republic of Indonesia acquires the citizenship of the Republic of Indonesia, if such an adoption is declared legal by the Pengadilan Negeri at the residence of the person adopting the child." Obama's mother married Soetoro in 1966 or 1967 - the date isn't clear - and moved to Indonesia in 1967. Obama would have been older than 5 when they returned, so Indonesian citizenship was not automatic. He would have had to wait until he was 21.
Ok you win. Go have a beer
Have a nice night.