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A278242
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Least number with the prime signature of 2^n + 1.
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3
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2, 2, 2, 4, 2, 6, 6, 6, 2, 24, 12, 6, 6, 6, 30, 60, 2, 6, 210, 6, 6, 60, 30, 6, 30, 210, 210, 240, 6, 30, 4620, 6, 6, 420, 210, 2310, 210, 30, 210, 60, 6, 30, 30030, 6, 30, 9240, 2310, 30, 30, 30, 9240, 4620, 30, 30, 30030, 4620, 30, 420, 30, 210, 210, 6, 2310, 9240, 6, 30030, 30030, 30, 60, 420, 60060, 30, 2310, 30, 2310, 60060, 210, 30030, 446185740, 6, 30
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refs;
listen;
history;
text;
internal format)
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OFFSET
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0,1
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LINKS
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FORMULA
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MATHEMATICA
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Table[Times @@ MapIndexed[(Prime@ First@ #2)^#1 &, #] &@ If[Length@ # == 1 && #[[1, 1]] == 1, {0}, Reverse@ Sort@ #[[All, -1]] &@ FactorInteger[ 2^n + 1], {n, 77}] (* Michael De Vlieger, Nov 21 2016 *)
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PROG
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(PARI)
for(n=0, 257, write("b278242.txt", n, " ", A278242(n)));
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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