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A181704
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Numbers m=2^(t-1)*(2^t-5), where 2^t-5 is prime.
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2
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12, 88, 1888, 32128, 521728, 8378368, 34359083008, 549753192448, 2251799645913088, 9223372026117357568, 2361183241263023915008, 2596148429267413634121263069790208, 2722258935367507707522529418717050175488
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OFFSET
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1,1
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COMMENTS
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All these numbers are in A181595 because their abundance is 4, a proper divisor of m.
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LINKS
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Table of n, a(n) for n=1..13.
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MATHEMATICA
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Rest[2^(#-1) (2^#-5)&/@(Round[N[Log[#+5]/Log[2]]]&/@Select[Table[2^t-5, {t, 120}], PrimeQ])] [From Harvey P. Dale, Dec. 16, 2010]
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CROSSREFS
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Cf. A059608, A156560, A181595, A181701, A000396, A181703, A045769
Sequence in context: A081009 A155635 A126507 * A009657 A012088 A083825
Adjacent sequences: A181701 A181702 A181703 * A181705 A181706 A181707
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KEYWORD
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nonn
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AUTHOR
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Vladimir Shevelev, Nov 06 2010
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EXTENSIONS
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571728 replaced by 521728 - R. J. Mathar, Dec 05 2010
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STATUS
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approved
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