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OK but I knew all these things already.
Here is a slight but useful modification. In D5 instead of the instruction above put '=d$1*d4+c4', and copy that into a huge rectangle. The dollar sign, $, will cause the index that follows it to remain constant. Thus when you copy this into other rows and columns, d$1 will be the element of that column in the first row.
When you again put 1 in c4 you get numbers called "The Stirling numbers of the second kind".
Binomial coefficients count the number of subsets of an n element set having k elements in them. The Stirling number for arguments n and k here counts the number of partitions of a set of n elements into k disjoint blocks.
Exercises:
0.6 Set this up on your own machine. Solution
0.7 Binomial coefficients count the number of subsets of an n element set having k elements in them. The Stirling number here counts the number of partitions of a set of n elements into k disjoint blocks. Prove these two statements. Solution
0.8 Invent a good question for this spot.
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