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Search: id:A118979
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| A118979 |
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O.g.f: -12*x^3/(-1+x)/(-1+2*x)/(-1+3*x) = -2-2/(-1+3*x)-6/(-1+x)+6/(-1+2*x) . a(n) = 6*(1-2^n)+2*3^n = 12*A000392(n). |
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+0
3
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| 12, 72, 300, 1080, 3612, 11592, 36300, 111960, 342012, 1038312, 3139500, 9467640, 28501212, 85700232, 257493900, 773268120, 2321377212, 6967277352, 20908123500, 62736953400, 188236026012, 564758409672, 1694375892300
(list; graph; listen)
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OFFSET
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3,1
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COMMENT
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Negative of the determinant of a series of 3 X 3 matrices, related to Stirling's numbers of the second kind by a factor of 12 (cf. A000392, A028243).
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LINKS
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Index entries for sequences related to linear recurrences with constant coefficients
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FORMULA
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Let M = {{1, 1, 1}, {2^n, 4, 2}, {3^n, 9, 3}}. Then a(n) = -Det[M]
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MATHEMATICA
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M = {{1, 1, 1}, {2^n, 4, 2}, {3^n, 9, 3}} a = Table[ -Det[M], {n, 3, 30}]
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CROSSREFS
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Cf. A000392, A028243.
Sequence in context: A010024 A008414 A052181 this_sequence A014970 A036392 A035472
Adjacent sequences: A118976 A118977 A118978 this_sequence A118980 A118981 A118982
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KEYWORD
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nonn
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AUTHOR
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Roger L. Bagula (rlbagulatftn(AT)yahoo.com), May 25 2006
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EXTENSIONS
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Edited by N. J. A. Sloane (njas(AT)research.att.com), Dec 13 2007
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