Sunan an-Nasa'i, Hadith 1329 ⓘ
It was narrated from 'Abdullah that: The Prophet said the salam, then he spoke, then he performed two prostrations of forgetfulness.
أَخْبَرَنَا مُحَمَّدُ بْنُ آدَمَ، عَنْ حَفْصٍ، عَنِ الأَعْمَشِ، عَنْ إِبْرَاهِيمَ، عَنْ عَلْقَمَةَ، عَنْ عَبْدِ اللَّهِ، أَنَّ النَّبِيَّ صلى الله عليه وسلم سَلَّمَ ثُمَّ تَكَلَّمَ ثُمَّ سَجَدَ سَجْدَتَىِ السَّهْوِ .
also referenced under: Book 13, Hadith 151 (In-Book) & Volume 2, Book 13, Hadith 1330 (DarusSalam)