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Search: id:A140802
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| 1, 32, 640, 10240, 143360, 1835008, 22020096, 251658240, 2768240640, 29527900160, 307090161664, 3126736191488, 31267361914880, 307863255777280, 2990671627550720, 28710447624486912, 272749252432625664
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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>=3) of 9 objects: r, s, t, u, v, w, z, x, y with repetition allowed, containing exactly (3) three u's.
Example:
(n=4) a(1)=32
uuur, uuru, uruu, ruuu,
uuus, uusu, usuu, suuu,
uuut, uutu, utuu, tuuu,
uuuv, uuvu, uvuu, vuuu,
uuuw, uuwu, uwuu, wuuu,
uuuz, uuzu, uzuu, zuuu,
uuux, uuxu, uxuu, xuuu,
uuuy, uuyu, uyuu, yuuu
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MAPLE
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seq(binomial(n+3, 3)*8^n, n=0..19);
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PROGRAM
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(Other) SAGE:[lucas_number2(n, 8, 0)*binomial(n, 3)/8^3 for n in xrange(3, 20)] # [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Mar 13 2009]
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CROSSREFS
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Sequence in context: A036903 A013699 A004337 this_sequence A028204 A028190 A028202
Adjacent sequences: A140799 A140800 A140801 this_sequence A140803 A140804 A140805
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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), Jul 15 2008
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