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A022149 Coordination sequence for root lattice B_7. 4
1, 98, 1946, 16394, 83442, 307314, 907018, 2282394, 5095650, 10368386, 19594106, 34866218, 59021522, 95799186, 150015210, 227752378, 336565698, 485703330, 686343002, 951843914, 1298014130, 1743393458 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

REFERENCES

R. Bacher, P. de la Harpe and B. Venkov, Series de croissance et series d'Ehrhart associees aux reseaux de racines, C. R. Acad. Sci. Paris, 325 (Series 1) (1997), 1137-1142.

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..1000

M. Baake and U. Grimm, Coordination sequences for root lattices and related graphs, arXiv:cond-mat/9706122, Zeit. f. Kristallographie, 212 (1997), 253-256.

Index entries for linear recurrences with constant coefficients, signature (7,-21,35,-35,21,-7,1).

FORMULA

a(0) = 1; for n>0, a(n) = (968*n^6 - 1368*n^5 + 5420*n^4 - 4080*n^3 + 4232*n^2 - 852*n + 90)/45 . - Philippe Deléham, Feb 20 2004

G.f.: -(x^7+371*x^6+2793*x^5+6155*x^4+4795*x^3+1281*x^2+91*x+1)/(x-1)^7 = 1 +2*x*(x+1) *(49+581*x+1834*x^2+1226*^2+181*x^4+x^5) /(1-x)^7. - Colin Barker, Nov 18 2012

MATHEMATICA

CoefficientList[Series[-(x^7 + 371 x^6 + 2793 x^5 + 6155 x^4 + 4795 x^3 + 1281 x^2 + 91 x + 1)/(x - 1)^7, {x, 0, 30}], x] (* Vincenzo Librandi, Oct 16 2013 *)

LinearRecurrence[{7, -21, 35, -35, 21, -7, 1}, {1, 98, 1946, 16394, 83442, 307314, 907018, 2282394}, 30] (* Harvey P. Dale, Nov 20 2018 *)

CROSSREFS

Sequence in context: A019563 A285045 A197616 * A128801 A188484 A271037

Adjacent sequences:  A022146 A022147 A022148 * A022150 A022151 A022152

KEYWORD

nonn,easy

AUTHOR

mbaake(AT)sunelc3.tphys.physik.uni-tuebingen.de (Michael Baake)

STATUS

approved

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Last modified June 5 18:48 EDT 2020. Contains 334854 sequences. (Running on oeis4.)