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A190662 Least semiprime having prime factors that differ by 2*n!. 1

%I

%S 15,21,85,265,2761,10129,111001,887161,21047881,210471241,1037836969,

%T 68018232241,361167207241,3312775065961,49691625984361,

%U 1548286451713369,16361621692416529,294509190463488529

%N Least semiprime having prime factors that differ by 2*n!.

%e a(5) = 2761 because 2761 = 11 * 251 , and 251 - 11 = 240 = 2*120 = 2*5!

%t f[n_] := Block[{p=3}, While[! PrimeQ[p+2*n!], p=NextPrime[p]]; p (p + 2*n!)]; Table[f[n], {n, 60}]

%Y Cf. A190663.

%K nonn

%O 1,1

%A _Michel Lagneau_, May 16 2011

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Last modified February 22 07:03 EST 2020. Contains 332118 sequences. (Running on oeis4.)