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Search: id:A140325
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| 1, 18, 180, 1320, 7920, 41184, 192192, 823680, 3294720, 12446720, 44808192, 154791936, 515973120, 1666990080, 5239111680, 16066609152, 48199827456, 141764198400, 409541017600, 1163958681600, 3259084308480, 9001280471040
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OFFSET
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0,2
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COMMENT
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With a different offset, number of n-permutations (n>=8) of 3 objects: u, v, z with repetition allowed, containing exactly eight (8) u's.
If n=8 then a(0)= 1
Example: a(1)=18 because we have
uuuuuuuuv, uuuuuuuvu, uuuuuuvuu, uuuuuvuuu, uuuuvuuuu, uuuvuuuuu, uuvuuuuuu, uvuuuuuuu, vuuuuuuuu, uuuuuuuuz, uuuuuuuzu, uuuuuuzuu, uuuuuzuuu, uuuuzuuuu, uuuzuuuuu, uuzuuuuuu, uzuuuuuuu and zuuuuuuu.
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MAPLE
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seq(binomial(n+8, 8)*2^n, n=0..28);
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PROGRAM
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(Other) SAGE: [lucas_number2(n, 2, 0)*binomial(n, 8)/256 for n in xrange(8, 30)] [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Mar 10 2009]
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CROSSREFS
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Sequence in context: A071910 A121038 A004410 this_sequence A155669 A160954 A160955
Adjacent sequences: A140322 A140323 A140324 this_sequence A140326 A140327 A140328
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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), Jun 23 2008
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