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A115400 Number of n-colorings of the octahedral graph. 7
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; text; internal format)
OFFSET

0,4

COMMENTS

The octahedral graph is the dual of the cubical graph whose chromatic polynomial is evaluated in A140986.

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..10000

Eric W. Weisstein, Octahedral Graph.

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

MATHEMATICA

Table[n*(n-1)*(n-2)*(n^3-9*n^2+29*n-32), {n, 0, 50}] (* Vincenzo Librandi, Feb 12 2012 *)

PROG

(MAGMA) [n*(n-1)*(n-2)*(n^3 - 9*n^2 + 29*n - 32): n in [0..50]]; // Vincenzo Librandi, Feb 12 2012

(Maxima) A115400(n):=n*(n-1)*(n-2)*(n^3 - 9*n^2 + 29*n - 32)$

makelist(A115400(n), n, 0, 30); /* Martin Ettl, Nov 03 2012 */

CROSSREFS

Cf. A140986.

Sequence in context: A303212 A226549 A053338 * A279868 A055358 A030989

Adjacent sequences:  A115397 A115398 A115399 * A115401 A115402 A115403

KEYWORD

easy,nonn

AUTHOR

Jonathan Vos Post, Aug 25 2008

STATUS

approved

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Last modified October 20 02:10 EDT 2019. Contains 328244 sequences. (Running on oeis4.)