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denis
Posts:
1
Registered:
8/7/09


sums of different binomial coefficients
Posted:
Aug 7, 2009 5:47 AM


Hello, I search a way to compute these sums : k = Sum[C(K(i),i),{i, p, 1}] where K(i) is a list like this : K(p) = n K(p1) = K(p)2 K(p2) = K(p1)1 K(p3) = n(p2)3 ... it's always decrementing but with arbitrary value n is a number ~10^10 (and greater) p is not greater as n/2
I search a way to compute it quickly. for n ~10^9 i have a way to compute it in 6 minutes but for n ~10^10 it takes me 15 hours...
Is there a way to rewrite the sums perhaps in a way it will be faster to calculate ?
my usage is to calculate the combinadic on files greater than 1Mo.
Thanks by advance for your suggestions.



