Shiva Purana
पंचाक्षरं पंचलक्षं जपेच्छिवमनुस्मरन् । पद्मासनस्थं शिवदं गंगाचंद्र कलान्वितम् ३८ ।
One should chant the Panchakshara mantra 5 lakh times, meditating on Lord Shiva, seated in Padmasana, adorned with the Ganga, the moon, and other divine symbols.
english translation
paMcAkSaraM paMcalakSaM japecchivamanusmaran । padmAsanasthaM zivadaM gaMgAcaMdra kalAnvitam 38 ।
hk transliteration by Sanscript