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Search: id:A094261
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| A094261 |
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a(n)=n(n-1)(n-3)(n-6)...(n-t), where t is the largest triangular number less than n; number of factors in the product is ceil([sqrt(1+8*n)-1]/2). |
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1
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| 1, 2, 6, 12, 40, 90, 168, 560, 1296, 2520, 4400, 14256, 32760, 64064, 113400, 187200, 586432, 1321920, 2560896, 4522000, 7484400, 11797632, 35784320, 78871968, 150480000, 263120000, 433060992, 681080400, 1033305728, 3044304000
(list; graph; listen)
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OFFSET
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1,2
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EXAMPLE
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a(8)=8(8-1)(8-3)(8-6)=8*7*5*2=560.
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MAPLE
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a:=n->product(n-k*(k+1)/2, k=0..ceil((sqrt(1+8*n)-1)/2)-1): seq(a(n), n=1..35); (Deutsch)
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CROSSREFS
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Cf. A094262.
Sequence in context: A074442 A162589 A123045 this_sequence A080497 A127724 A056744
Adjacent sequences: A094258 A094259 A094260 this_sequence A094262 A094263 A094264
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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), Apr 26 2004
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EXTENSIONS
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Corrected and extended by Emeric Deutsch (deutsch(AT)duke.poly.edu), Feb 03 2006
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