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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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0
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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; refs; listen; history; internal format)
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OFFSET
| 1,2
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EXAMPLE
| a(8)=8(8-1)(8-3)(8-6)=8*7*5*2=560.
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MAPLE
| 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
| Cf. A094262.
Sequence in context: A204515 A162589 A123045 * A080497 A127724 A178008
Adjacent sequences: A094258 A094259 A094260 * A094262 A094263 A094264
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KEYWORD
| nonn
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AUTHOR
| Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Apr 26 2004
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EXTENSIONS
| Corrected and extended by Emeric Deutsch (deutsch(AT)duke.poly.edu), Feb 03 2006
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