The sum of the last and the one before the last is the number ... of the next mātrā-vṛtta.

Hemachandra (c. 1150), in Livio, Mario (2003) [2002], The Golden Ratio: The Story of Phi, the World's Most Astonishing Number [archive] (First trade paperback ed.), New York City: Broadway Books, ISBN 0-7679-0816-3, and in Shah, Jayant (1991), A History of Piṅgala's Combinatorics, Northeastern University