Reference for Niddah 127:6

נימא רב ושמואל בפלוגתא דרבי ורשב"ג קמיפלגי

differ here: Rab holds that the fifteenth day is included in the number while Samuel holds that the fifteenth, since the observation on it was not in arithmetic progression, is not included in the number.<span class="x" onmousemove="('comment',' Cf. prev. n. but three. ');">⁶</span>

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