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<DIV><FONT face=Arial size=2>Dear SeqFan,</FONT></DIV>
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<DIV><FONT face=Arial size=2>Let a(n) = n!.2^n +1</FONT></DIV>
<DIV><FONT face=Arial size=2>a(n) is prime for n=1 and n=259 but there are no
other prime for n<2650</FONT></DIV>
<DIV><FONT face=Arial size=2>Can any one extend this sequence ?</FONT></DIV>
<DIV><FONT face=Arial size=2> I remark that if p is prime then p divide
a(p-1)</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>we can prove this by wilson's theorem and Fermat's
Little Theorem</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>if p is prime and gcd(q,p)=1 then p divide
(p-1)!.q^(p-1) + 1</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
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<DIV><FONT face=Arial size=2>Thanks</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>M.Bouayoun</FONT></DIV>
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