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Search: id:A090904
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| A090904 |
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Group the natural numbers so that the n-th group product is a multiple of the (n-1)th group product. (1), (2),(3,4), (5,6,7,8),(9,10,11,12,13,14),(15,16,17,18,19,20,21,22,23,24,25,26),... Sequence contains the product of terms of the groups. |
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5
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| 1, 2, 12, 1680, 2162160, 4626053752320000, 13644281345408020027550269440000, 4402827357584746886229433170489943024971625310770489684257669120000000000
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OFFSET
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1,2
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COMMENT
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Conjecture: For n > 4 the last term of the n-th group is 2p where p is the largest prime in the (n-1)th group. And these are the Bertrand primes.
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CROSSREFS
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Cf. A090905, A090906, A090907.
Sequence in context: A111180 A085912 A085895 this_sequence A125295 A050649 A003042
Adjacent sequences: A090901 A090902 A090903 this_sequence A090905 A090906 A090907
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KEYWORD
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nonn
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AUTHOR
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Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Dec 13 2003
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EXTENSIONS
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More terms from David Wasserman (wasserma(AT)spawar.navy.mil), Feb 10 2006
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