Shiva Purana
अङ्गुल्या जपसंख्यानमेकमेवमुदाहृतम् ॥ रेखयाष्टगुणं विद्यात्पुत्रजीवैर्दशाधिकम् ॥ ३४ ॥
The number of mantras chanted by the fingers is thus described as one. It is known to be eight times the line and more than ten times the life of the son.
english translation
aGgulyA japasaMkhyAnamekamevamudAhRtam ॥ rekhayASTaguNaM vidyAtputrajIvairdazAdhikam ॥ 34 ॥
hk transliteration by Sanscript