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Search: id:A057265
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| A057265 |
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Even refactorable numbers (i.e. the number of divisors is itself a divisor and it is also even). |
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+0
9
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| 2, 8, 12, 18, 24, 36, 40, 56, 60, 72, 80, 84, 88, 96, 104, 108, 128, 132, 136, 152, 156, 180, 184, 204, 228, 232, 240, 248, 252, 276, 288, 296, 328, 344, 348, 360, 372, 376, 384, 396, 424, 444, 448, 450, 468, 472, 480, 488, 492
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Invented by the HR mathematical theory formation program.
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REFERENCES
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S. Colton, Unpublished PhD Thesis, University of Edinburgh, 2000
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LINKS
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S. Colton, Refactorable Numbers - A Machine Invention, J. Integer Sequences, Vol. 2, 1999, #2.
S. Colton, HR - Automatic Theory Formation in Pure Mathematics
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EXAMPLE
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18 is refactorable because tau(18) = 6 and 6 divides 18, and 18 is even.
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CROSSREFS
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Cf. A033950, A036896.
Sequence in context: A005880 A046470 A090772 this_sequence A046525 A099418 A108987
Adjacent sequences: A057262 A057263 A057264 this_sequence A057266 A057267 A057268
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KEYWORD
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easy,nonn
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AUTHOR
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Simon Colton (simonco(AT)cs.york.ac.uk), Aug 21 2000
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