Pascal’s Triangle
 Figure 1 |
Consider the triangle in Figure 1, called Pascal’s triangle. It consists of numbers where each entry is the sum of the two entries above it.
Do you recognize the numbers in each row? This a quick way to generate the coefficients of (x+y)n from algebra!
And, better yet, you can use them as a quick way to calculate the powers of 11, since 11=10+1. Notice that 11, 121, 1331, and 14641 are all powers of 11…
sumber: http://www.math.hmc.edu/funfacts/ffiles/10001.1-4-5.shtml
