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Search: id:A141480
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| 125, 500, 1250, 2500, 4375, 7000, 10500, 15000, 20625, 27500, 35750, 45500, 56875, 70000, 85000, 102000, 121125, 142500, 166250, 192500, 221375, 253000, 287500, 325000, 365625, 409500, 456750, 507500, 561875, 620000, 682000, 748000, 818125
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OFFSET
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0,1
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COMMENT
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Number of n permutations (n>=3) of 6 objects t, u, v, z, x, y with repetition allowed, containing n-3 u's. Examples:
if n=3 then n-3=zero (0) u, a(1)=125,
if n=4 then n-3= one (1) u, a(2)=500,
if n=5 then n-3= two (2) u, a(3)=1250,
if n=6 then n-3= three (3) u, a(3)=1250, etc...
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FORMULA
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G.f.:125/(1-x)^4. a()n)=C(n+2,3)*5^3, n>=1.
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MAPLE
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seq(binomial(n+2, 3)*5^3, n=1..44);
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CROSSREFS
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Sequence in context: A161855 A045184 A059470 this_sequence A155986 A128993 A061450
Adjacent sequences: A141477 A141478 A141479 this_sequence A141481 A141482 A141483
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KEYWORD
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nonn
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AUTHOR
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Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Aug 09 2008
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