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*To*: [email protected]*Subject*: Fast Modular Factorial?*From*: [email protected] (Mike Duvos)*Date*: Fri, 23 Sep 1994 09:34:34 -0700 (PDT)*Sender*: [email protected]

A small question about large integer math... We are all familar with the fact that x^(2^n) mod p may be evaluated with only n modmults which accumulate geometrically increasing powers of x. Does a similar fast algorithm exist for computing (2^n)! mod p? The only difference here is that one is accumulating a huge product of consecutive integers instead of the same integer multiplied many times. I am interested in values of n around several hundred. I have played with this quite a bit and am unable to see any easy exploitable symmetry which would lead to an efficient algorithm. Any ideas? -- Mike Duvos $ PGP 2.6 Public Key available $ [email protected] $ via Finger. $

**Follow-Ups**:**Re: Fast Modular Factorial?***From:*Matthew J Ghio <[email protected]>

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