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Search: id:A111682
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| A111682 |
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a(n)=(2n)^(2n)-(2n-1)!*(3n)!/((n-1)!(2n)!). |
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+0
1
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| 1, 76, 16416, 6798016, 4551356800, 4470007597056, 6043460975190016, 10752691472850927616, 24343005503622220775424, 68309311335401364275200000, 232660170298374017479641923584
(list; graph; listen)
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OFFSET
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1,2
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EXAMPLE
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2^2 - 1*3 =1 = a(1)
4^4 - 2*3*5*6 = 256 - 180 =76 = a(2)
6^6 - 3*4*5*7*8*9 = 46656 - 30240 =16416 =a(3)
8^8 - 4*5*6*7*9*10*11*12 =6798016 = a(4)
...
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MAPLE
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a:=n->(2*n)^(2*n)-(2*n-1)!*(3*n)!/(n-1)!/(2*n)!: seq(a(n), n=1..13); # (Deutsch)
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CROSSREFS
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Sequence in context: A093276 A093238 A028480 this_sequence A033521 A060716 A116255
Adjacent sequences: A111679 A111680 A111681 this_sequence A111683 A111684 A111685
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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), Aug 16 2005
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EXTENSIONS
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More terms from Emeric Deutsch (deutsch(AT)duke.poly.edu), Aug 27 2005
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