posted by Linda on .
A design starts with 1 tile and it continues to grow the next day to 4 tiles and on the third day there is 13 tiles. How many tiles will there be on the 10th day? How many tiles on the 50th day? Find a formula for any number?
Since 1 , 4, 13 do not form either an arithmetic nor a geometric sequence,
having only 3 terms is not enough information to see the pattern
e.g. I could claim that the sequence is
1 4 13 40 121 by claiming that I add increasing powers of 3 to get the next term
1+3 = 4
4+9 = 13
13+27 = 40
40 +81 = 121