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Search: id:A143357
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| A143357 |
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Floor((n-1)!/[n(n+1)]). |
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+0
1
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| 0, 0, 0, 0, 0, 2, 12, 70, 448, 3298, 27490, 255876, 2631876, 29652480, 363242880, 4807626352, 68375130352, 1040021719578, 16848351857178, 289631191449600, 5266021662720000, 100970241446066086, 2036233202495666086
(list; graph; listen)
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OFFSET
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1,6
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COMMENT
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All terms are even.
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REFERENCES
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T. Andreescu, D. Andrica and Z. Feng, 104 Number Theory Problems (from the training of the USA IMO team), Birkhauser, Boston, 2007, Introductory problem # 50, pp. 82,126,127.
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MAPLE
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seq(floor(factorial(n-1)/(n*(n+1))), n=1..25);
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CROSSREFS
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Adjacent sequences: A143354 A143355 A143356 this_sequence A143358 A143359 A143360
Sequence in context: A001542 A059229 A001251 this_sequence A012426 A012421 A012381
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KEYWORD
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nonn
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AUTHOR
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Emeric Deutsch (deutsch(AT)duke.poly.edu), Aug 11 2008
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