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Search: id:A053469
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| A053469 |
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A second order recursive relation. |
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+0
6
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| 1, 12, 108, 864, 6480, 46656, 326592, 2239488, 15116544, 100776960, 665127936, 4353564672, 28298170368, 182849716224, 1175462461440, 7522959753216, 47958868426752, 304679870005248, 1929639176699904, 12187194800209920
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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With a different offset, number of n-permutations of 7 objects q, u, v, w, z, x, y with repetition allowed, containing exactly one u. - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Dec 28 2007
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REFERENCES
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A. H. Beiler, Recreations in the Theory of Numbers, Dover, N.Y., 1964, pp. 194-196.
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LINKS
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F. Ellermann, Illustration of binomial transforms
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FORMULA
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a(n)=n(6^(n-1)), n>0. a(n)=12a(n-1)-36a(n-2), n>0; a(0)=1.
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MAPLE
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a:=n->sum (6^n, j=0..n): seq(a(n), n=0..19); - ZerinvaryLajos (zerinvarylajos(AT)yahoo.com), Oct 02 2007
seq(seq(binomial(i, j)*6^(i-1), j =i-1), i=1..20); # - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Dec 28 2007
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CROSSREFS
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Cf. A002697 and A027471.
Sequence in context: A089396 A037972 A111990 this_sequence A055533 A037602 A037707
Adjacent sequences: A053466 A053467 A053468 this_sequence A053470 A053471 A053472
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KEYWORD
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easy,nonn
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AUTHOR
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Barry E. Williams, Jan 13 2000
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EXTENSIONS
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More terms from James A. Sellers (sellersj(AT)math.psu.edu), Feb 02 2000
More terms from ZerinvaryLajos (zerinvarylajos(AT)yahoo.com), Oct 02 2007
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