Fasting and worshiping Lord Vishnu on Akshaya Tritiya gives the results of Rajasuya yaga - Matsya Purana.
Writing down a mantra or a nama instead of chanting it is called likhita japa. Namatraya astra mantra is very effective if you perform likhita japa instead of oral or mental chanting. People fill out books doing likhita japa and keep them at home as an armor.
ह्रूं ह्रूं महाकाल प्रसीद प्रसीद ह्रीं ह्रीं स्वाहा hroom hroom mahaakaala praseeda praseeda hreem hreem svaahaa....
ह्रूं ह्रूं महाकाल प्रसीद प्रसीद ह्रीं ह्रीं स्वाहा
hroom hroom mahaakaala praseeda praseeda hreem hreem svaahaa