Source of Ramayana Mantra

Question

Please let me know the source of shloka

राघवो विजयं दद्यात् मम सीतापतिः प्रभुः ।
राघवस्य यथत्द्वन्द्वं दद्यात् वैभवम् ॥

raaghavo vijayam dadyAt mama sItApatiH prabhuH|
raaghavasya yathatdvandvam dadyAt amita vaibhavam||

Meaning:
May Raaghavan, the Lord of SeethA PirAtti grant me victory in my kaimkaryams! May His sacred pair of feet bless me with limitless glory of Kaimkaryam to Him !

I want to know from where this mantra has been picked

Answer 1

This shloka was given by Ramanuja Acharya as a mantra for Sundarakanda. I am not sure about the Hindi letters but in Telugu, letters are allotted certain number. So when you take the first sentence राघवो विजयं दद्यात् मम सीतापतिः प्रभुः । or in Telugu when each letter is given the value

రా ఘ వో వి జ యo ద ధ్వాన్ మ మ సీ తా ప తి: ప్ర భు: = no of letters = 16 (16 days) 2 4 4 4 8 1 8 1 5 5 7 6 1 6 2 4 = 68(68 Sargas in Sundara Kanda)

So best way of doing Sundarakanda Parayana is for 16 days and each day you should read the no of Sargas as the numbers allocated for the mantra. example: first day 2 Sargas, second day 4, third day 4......so on..

This information was provided by Nanduri Srinivas in one of his Youtube videos about Sundarakand