All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
We have not come across what you mentioned except what is reported regarding Aayatul-Kursi [Quran 2:255]. Ibn Hibbaan reported that the Prophet said: “Whoever recites Ayatul-Kursi after each obligatory prayer, then nothing can prevent him from entering Paradise except death.”
The Hadeeth was classified by Shaykh Al-Albaani as Saheeh (sound).
For more benefit on the legislated Athkaar (mention of Allaah) after the obligatory prayer, please refer to Fatwa 81736.
Allaah Knows best.