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Search: id:A081136
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| A081136 |
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6th binomial transform of (0,0,1,0,0,0,........). |
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+0
5
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| 0, 0, 1, 18, 216, 2160, 19440, 163296, 1306368, 10077696, 75582720, 554273280, 3990767616, 28298170368, 198087192576, 1371372871680, 9403699691520, 63945157902336, 431629815840768, 2894458765049856, 19296391766999040
(list; graph; listen)
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OFFSET
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0,4
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COMMENT
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Starting at 1, three-fold convolution of A000400 (powers of 6).
Number of n-permutations (n=3) of 7 objects: p, u, v, w, z, x, y with repetition allowed, containing exactly two u's. - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), May 23 2008
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FORMULA
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a(n)=18a(n-1)-108a(n-2)+216a(n-3), a(0)=a(1)=0, a(2)=1. a(n)=6^(n-2)C(n, 2). G.f. x^2/(1-6x)^3.
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MAPLE
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seq(binomial(n+2, 2)*6^n, n=-2..19); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), May 23 2008
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CROSSREFS
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Cf. A038845, A027472, A081135.
Sequence in context: A059357 A009470 A111991 this_sequence A101188 A019757 A021503
Adjacent sequences: A081133 A081134 A081135 this_sequence A081137 A081138 A081139
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KEYWORD
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easy,nonn
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AUTHOR
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Paul Barry (pbarry(AT)wit.ie), Mar 08 2003
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