Pathamaniddasasutta 5.6

5.6

chattiṃsati cepi vassāni paripuṇṇaṃ parisuddhaṃ brahmacariyaṃ carati, ‘niddaso bhikkhū’ti alaṃvacanāya, aṭṭhacattārīsañcepi vassāni paripuṇṇaṃ parisuddhaṃ brahmacariyaṃ carati, ‘niddaso bhikkhū’ti alaṃvacanāyā”ti.

thirty-six years, or forty-eight years.”