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A135386
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Mersenne composites A065341 with 4 or more prime factors.
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1
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OFFSET
| 1,1
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MAPLE
| A135386 := proc(n) local i;
i := 2^(ithprime(n))-1:
if (nops(numtheory[factorset](i)) > 3) then
RETURN (i)
fi: end: seq(A135386(n), n=1..37); # - Jani Melik, Feb 09 2011
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MATHEMATICA
| k = {}; Do[If[ ! PrimeQ[2^Prime[n] - 1], c = FactorInteger[2^Prime[n] - 1]; d = Length[c]; If[d >3, AppendTo[k, 2^Prime[n] - 1]]], {n, 1, 40}]; k
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CROSSREFS
| Subsequence of A065341.
Cf. A000225, A054723, A134852, A135975, A135976, A135977, A135979.
Sequence in context: A083103 A115532 A074194 * A095462 A115543 A095464
Adjacent sequences: A135383 A135384 A135385 * A135387 A135388 A135389
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KEYWORD
| nonn,bref
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AUTHOR
| Artur Jasinski (grafix(AT)csl.pl), Dec 09 2007
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