By the Grace of God and Guru,
In the the book, "Sri Gayatri" revealed by Karunamayi Amma of www.karunamayi.org ,
there is the Gayatri Sanjivini Mantra on page 109:
"Today, Amma will tell you about sanjivini vidya,
the knowledge of the rejuvenating energy
concealed in the Sri Gayatri Mantra:
Om trayambakam yajamahe
Om bhur bhuvah suvah tat savitur varenyam
Om sugandim pusti vardenam
Om bhargo devasya dhimahi
Om urva rukamiva bandahanat
Om dhiyo yonah prachodayat
Om mrtyor muksiya mamritat
This is the Gayatri sanjivini vidya.
It is necessary to be initiated into this maha mantra by a Sadguru,
a fully illumined Guru.
You can acquire the power of sanjivini vidya by repeating this mantra as
many lakhs of times as the total number of seed syllables in the mantra.
This incredibly powerful maha mantra is the combination of
Sri Gayatri Mantra and Sri Maha Mrityunjaya Mantra.
Sri Gayatri Mantra fills the hearts of those who chant it
and meditate on it with tender compassion.
That is why Amma just told you about the Sanjivini Mantra."
end of excerpt.
No more is said or written about it
i believe a lakh is 1 hundred thousand - 100,000 times, the Gayatri Mantra seems to has 30 syllables plus the lokas and the Mrityunjaya seems to have 34 plus the extra om's of 5 would be 69(?) syllables - lakhs,therefore 69 x 100,000 = 6,900,000.
And my intuition tells me that you can add the Om Haum Jum Sah prefix bijas and Om Sah Jum Haum Om suffix bijas that go with the Mrityunjaya Mantra to it.
In service of God and Guru,