1

Part of 2009 Regional Olympiad of Mexico Northeast

Problems(1)

sequence of numbers defined by diagonal of a numbered square spiral

Source: IX - Mathematics Regional Olympiad of Mexico Northeast 2009 P1

Consider the sequence

\{1,3,13,31,...\}

that is obtained by following diagonally the following array of numbers in a spiral. Find the number in the

100

th position of that sequence.
https://cdn.artofproblemsolving.com/attachments/b/d/3531353472a748e3e0b1497a088472691f67fd.png

Sequencealgebra