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A156893
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Primes of the form 1 + 2 * Product_{i=1..k} (2^i-1).
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1
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OFFSET
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1,1
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COMMENTS
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LINKS
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EXAMPLE
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For n=4, 2*(2^1 - 1)*(2^2 - 1)*(2^3 -1)*(2^4 - 1) + 1 = 2*1*3*7*15 + 1 = 631
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MAPLE
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R:= NULL: count:= 0: v:= 1:
for k from 1 while count < 10 do
v:= v*(2^k-1);
p:= 1+2*v;
if isprime(p) then R:= R, p; count:= count+1 fi
od:
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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