Question 1049265
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A pyramid of blocks is built in layers.  The bottom layer has 6^2 or 36 blocks.  The next layer is 5^2 or 25 blocks 
and so on until the top layer has 1 block.  How many blocks are there in all?
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1^2 + 2^2 + 3^2 + 4^2 + 5^2 + 6^2 = {{{6*7*(2*6+1)/6}}} = calculate it yourself.


1^2 + 2^2 + 3^2 + . . . + n^2 = {{{(n*(n+1)*(2n+1))/6}}}.


See the lesson

&nbsp;&nbsp;&nbsp;&nbsp;- <A HREF=http://www.algebra.com/algebra/homework/Sequences-and-series/Mathematical-induction-for-sequences-other-than-arithmetic-or-geometric.lesson>Mathematical induction for sequences other than arithmetic or geometric</A>

in this site.
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