Allāhumma innī as'aluka `ilman nāfi`an,
wa rizqan ṭayyiban, wa `amalam-mutaqabbala.
[to be said after giving salam for the Fajr prayer.]
"O Allah, I ask You for knowledge which is beneficial,
and sustenance which is good, and deeds which are acceptable."
Reference:
Ibn Majah and others. See Sahih Ibn Majah 1/152 and Majma' Az-Zawa'id 10/111