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Largest prime factor of the least number having exactly two odd prime factors that differ by 2*n^2.
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%I #4 Mar 30 2012 18:35:55

%S 5,11,23,37,53,79,101,131,167,211,271,293,349,397,457,523,601,653,727,

%T 811,887,971,1061,1163,1279,1381,1471,1571,1693,1811,1933,2053,2207,

%U 2341,2467,2609,2741,2917,3049,3203,3373,3533,3701,3877,4057,4243,4421,4621,4813,5003,5209

%N Largest prime factor of the least number having exactly two odd prime factors that differ by 2*n^2.

%C The least number having exactly two odd prime factors that differ by 2*n^2 is given by the sequence A190052 .

%e a(11) = 271 because A190052(11) = 7859 =29 * 271 , and 271 is the largest prime

%e divisor such that 271 - 29 = 242 = 2*11^2.

%p with(numtheory):for m from 1 to 60 do: k:=2*m^2:id:=0:for n from 1 to 100000

%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, `,x[2]):else fi:od:od:

%Y Cf. A190052.

%K nonn,easy

%O 1,1

%A _Michel Lagneau_, May 05 2011