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A218849 Primes p such that 4*p is greater than  the greatest prime factor of  p^4 -1 and p^4 + 1. 0

%I

%S 2383,3373,10181,11483,18979,30727,35677,35837,37783,41879,41893,

%T 47041,48131,49253,53309,55541,62497,67103,84229,88607,91499,95869,

%U 97397,99523,104161,105557,107747,113149,118493,118927,137339,145501,146291,148153,149713,165701

%N Primes p such that 4*p is greater than the greatest prime factor of p^4 -1 and p^4 + 1.

%e 2383^4 - 1 = 2^6*3*5*149*157*397*3617, 2383^4 + 1 = 2*809*857*2833*8209 and 4*2383 > 8209 and 4*2383 > 3617.

%t Select[Prime[Range[PrimePi[200000]]], 4 # > FactorInteger[#^4 - 1][[-1, 1]] && 4 # > FactorInteger[#^4 + 1][[-1, 1]] &] (* _T. D. Noe_, Nov 07 2012 *)

%o (PARI) forprime(h=3,200001,for(n=4,4,a=h^n; b=a-1; c=a+1; d=vecmax(factor(b)[,1]~); e=vecmax(factor(c)[,1]~); g=h*n; if(g>d && g>e,print1(h,", "))))

%K nonn

%O 1,1

%A _Robin Garcia_, Nov 07 2012

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Last modified October 24 02:02 EDT 2021. Contains 348217 sequences. (Running on oeis4.)