I don't see an operator between arr[0][0] and arr[1][0], so I presume the parenthesis mean you want to multiply.

Your description does not adequately explain what you want, particularly the (a[N-1][0] + a[N-1][1]).

Indices from your example: 

0,0 1,0
0,0 1,1
0,1 1,0
0,1 1,1

[download]
Don't follow. They should be: 
0,0 1,0
0,0 1,1
1,0 1,0
1,1 1,1
2,0 1,0
2,1 1,1
3,0 1,0
3,1 1,1
...

[download]
The wrong element is incrementing -- a[0][N-1] * a[1][0], a[0][N-1] * a[1][1].

Furthermore, this makes no sense. Are a[0][1] and a[1][1] use repeatedly throughout? If so, why not change them into constants?

Celebrate Intellectual Diversity

In reply to Re^3: Obtaining terms in an expansion by InfiniteSilence
in thread Obtaining terms in an expansion by randyk

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