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Discussion of Problem 2079. Memory leaks

Xn+1==(sqrt(5*Xn*Xn+4*(-1)^n)+Xn)/2
Posted by Shen Yang 2 Dec 2017 09:23
rt
Re: Xn+1==(sqrt(5*Xn*Xn+4*(-1)^n)+Xn)/2
Posted by Shen Yang 2 Dec 2017 15:17
first for bound=1e5,using matirx power to compute x0,x1  x[bound],x[bound+1] ,x[2*bound],x[2*bound+1].....  upper bound is 2*p   using map to record  (x[i*bound],x[i*bound+1])

I use this formula and discrete log algo to find candidate of xn+1

then continue to compute xn-1 xn-2 .... until we find (xi,xi+1) in the map then it is valid
otherwise it is invalid
complex : sqrt(p*log(p))

Edited by author 02.12.2017 15:17