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Search: id:A133024
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| A133024 |
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Divisors of 8128, the 4th perfect number. |
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+0
6
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| 1, 2, 4, 8, 16, 32, 64, 127, 254, 508, 1016, 2032, 4064, 8128
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OFFSET
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1,2
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COMMENT
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127 is the 4th Mersenne prime: A000668.
The number of divisors of the 4th perfect number is 2*A000043(4)=A061645(4)=14.
For the structure of this sequence and its binary expansion, see A135654.
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LINKS
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O. E. Pol, Determinacion geometrica de los numeros primos y perfectos.
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FORMULA
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For n=1..7 : a(n) = 2^(n-1). For n=8..14: a(n) = 2^(n-1) - 2^(n-8) = A000668(4)*2^(n-8).
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CROSSREFS
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Cf. A018254, A018487. Perfect numbers: A000396.
Cf. A000079, A000668, A061645, A133033, A135654.
Sequence in context: A062258 A066178 A122189 this_sequence A060376 A047869 A016025
Adjacent sequences: A133021 A133022 A133023 this_sequence A133025 A133026 A133027
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KEYWORD
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fini,full,nonn
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AUTHOR
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Omar E. Pol (info(AT)polprimos.com), Oct 26 2007, Mar 03 2008, Dec 27 2008
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