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A115400
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Number of n-colorings of the octahedral graph.
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2
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0, 0, 0, 6, 96, 780, 4080, 15330, 45696, 115416, 257760, 523710, 987360, 1752036, 2957136, 4785690, 7472640, 11313840, 16675776, 24006006, 33844320, 46834620, 63737520, 85443666, 112987776, 147563400, 190538400, 243471150, 308127456
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,4
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COMMENTS
| The octahedral graph is the dual of the cubical graph whose chromatic polynomial is evaluated in A140986.
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LINKS
| Vincenzo Librandi, Table of n, a(n) for n = 0..10000
Eric W. Weisstein, Octahedral Graph.
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FORMULA
| a(n) = n*(n-1)*(n-2)*(n^3 - 9*n^2 + 29*n - 32).
G.f.: 6*x^3*(1+9*x+39*x^2+71*x^3)/(1-x)^7. [Colin Barker, Feb 12 2012]
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MATHEMATICA
| Table[n*(n-1)*(n-2)*(n^3-9*n^2+29*n-32), {n, 0, 50}] (* Vincenzo Librandi, Feb 12 2012 *)
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PROG
| (MAGMA) [n*(n-1)*(n-2)*(n^3 - 9*n^2 + 29*n - 32): n in [0..50]]; // Vincenzo Librandi, Feb 12 2012
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CROSSREFS
| Cf. A140986.
Sequence in context: A196813 A179058 A053338 * A055358 A030989 A006044
Adjacent sequences: A115397 A115398 A115399 * A115401 A115402 A115403
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KEYWORD
| easy,nonn,changed
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AUTHOR
| Jonathan Vos Post (jvospost3(AT)gmail.com), Aug 25 2008
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