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A190663 Largest prime factor of the least semiprime whose prime factors differ by 2*n! 1

%I

%S 5,7,17,53,251,1447,10091,80651,725789,7257629,79833613,958003271,

%T 12454041629,174356582419,2615348736019,41845579776037,

%U 711374856192023,12804747411456023

%N Largest prime factor of the least semiprime whose prime factors differ by 2*n!

%e a(5) = 251 because A190662(5) = 2761 = 11 * 251 , and 251 is the largest prime

%e divisor such that 251 - 11 = 240 = 2*120 = 2*5!

%p with(numtheory):for m from 1 to 18 do: k:=2*m!:id:=0:for n from 1 to 900000000

%p while(id=0) do: x:=factorset(n):n1:=nops(x):n2:=bigomega(n):if n1=2 and n2=2

%p and x[2]=x[1]+k then id:=1:printf ( "%d %d \n", m, x[2]):else fi:od:od:

%Y Cf. A190662.

%K nonn

%O 1,1

%A _Michel Lagneau_, May 16 2011

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Last modified February 22 18:24 EST 2020. Contains 332148 sequences. (Running on oeis4.)