(2) Prayer (Kitab Al-Salat)
كتاب الصلاة
(347) Chapter: If One Prays Five Rak'ah
(198) باب إِذَا صَلَّى خَمْسًا
Sunan Abi Dawud 1021 
This tradition has also been transmitted by ‘Abd Allah (b. Mas’ud) through a different chain of narrators. This version goes; when one of you forgets (in his prayer), he should perform two prostrations. Then he turned away, and performed two prostrations (due to forgetfulness).

Abu Dawud said:

The narrator Husain also reported it like al-A'mash.

حَدَّثَنَا مُحَمَّدُ بْنُ عَبْدِ اللَّهِ بْنِ نُمَيْرٍ، حَدَّثَنَا أَبِي، حَدَّثَنَا الأَعْمَشُ، عَنْ إِبْرَاهِيمَ، عَنْ عَلْقَمَةَ، عَنْ عَبْدِ اللَّهِ، بِهَذَا قَالَ ‏ "‏ فَإِذَا نَسِيَ أَحَدُكُمْ فَلْيَسْجُدْ سَجْدَتَيْنِ ‏"‏ ‏.‏ ثُمَّ تَحَوَّلَ فَسَجَدَ سَجْدَتَيْنِ ‏.‏ قَالَ أَبُو دَاوُدَ رَوَاهُ حُصَيْنٌ نَحْوَ حَدِيثِ الأَعْمَشِ ‏.‏
Grade :  Sahih (Al-Albani) صحيح  (الألباني)حكم :
Reference : Sunan Abi Dawud 1021
In-book reference : Book 2, Hadith 632
English translation : Book 2, Hadith 1016