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A068482 Numbers n such that gcd(n!+1,2^n-1)>1.

%I A068482 #16 Oct 16 2018 20:09:35
%S A068482 2,3,4,6,10,12,16,18,22,23,28,30,36,39,40,42,46,51,52,58,60,63,66,70,
%T A068482 72,78,82,88,95,96,99,100,102,106,108,112,126,130,131,135,136,138,148,
%U A068482 150,156,162,166,172,178,180,183,190,191,192,196,198,210,215,222,226
%N A068482 Numbers n such that gcd(n!+1,2^n-1)>1.
%C A068482 If n=p-1, p prime, then n is in the sequence.
%H A068482 G. C. Greubel, <a href="/A068482/b068482.txt">Table of n, a(n) for n = 1..1000</a>
%p A068482 select(n->gcd(factorial(n)+1,2^n-1)>1,[$1..230]); # _Muniru A Asiru_, Oct 16 2018
%t A068482 Select[Range[300],GCD[#!+1,2^#-1]>1&] (* _Harvey P. Dale_, Jan 31 2015 *)
%o A068482 (PARI) isok(n) = gcd(n!+1,2^n-1) > 1; \\ _Michel Marcus_, Oct 16 2018
%o A068482 (GAP) Filtered([1..230],n->Gcd(Factorial(n)+1,2^n-1)>1); # _Muniru A Asiru_, Oct 16 2018
%Y A068482 Cf. A000225 (2^n-1), A038507 (n!+1).
%Y A068482 Cf. A068480, A068481, A068483.
%K A068482 easy,nonn
%O A068482 1,1
%A A068482 _Benoit Cloitre_, Mar 10 2002