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Search: id:A080309
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| A080309 |
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n-th even number equals n-th multiple of a Fermat number. |
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+0
2
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| 3, 5, 6, 9, 10, 12, 15, 17, 24, 25, 27, 30, 33, 34, 39, 40, 42, 45, 48, 50, 51, 60, 63, 65, 66, 68, 69, 70, 72, 75, 78, 80, 81, 95, 96, 111, 119, 120, 123, 125, 126, 129, 130, 132, 135, 136, 144, 159, 160, 174, 175, 177, 180, 183, 185, 186, 187, 189, 190, 192, 195, 204
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Sequence includes only multiples of Fermat numbers (sequence A080307), but not all of them. It is not certain that A080309 is infinite, but it seems likely given that exactly one-half of all integers are multiples of Fermat numbers (see A080307).
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EXAMPLE
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The first 3 even numbers are 2, 4, and 6; the first 3 multiples of Fermat numbers (the numbers of the form 2^(2^n)+1) are 3, 5, and 6. The third even number is also the third Fermat multiple; thus 3 is in the sequence.
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CROSSREFS
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Cf. A000215 (the Fermat numbers), A080307.
Sequence in context: A001969 A075311 A032786 this_sequence A018900 A126590 A140584
Adjacent sequences: A080306 A080307 A080308 this_sequence A080310 A080311 A080312
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KEYWORD
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nonn
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AUTHOR
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Matthew Vandermast (ghodges14(AT)comcast.net), Feb 16 2003
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