OFFSET
0,2
LINKS
Seiichi Manyama, Table of n, a(n) for n = 0..10000
M. Baake and U. Grimm, Coordination sequences for root lattices and related graphs, arXiv:cond-mat/9706122, Zeit. f. Kristallographie, 212 (1997), 253-256.
R. Bacher, P. de la Harpe and B. Venkov, Séries de croissance et séries d'Ehrhart associées aux réseaux de racines, C. R. Acad. Sci. Paris, 325 (Series 1) (1997), 1137-1142.
Index entries for linear recurrences with constant coefficients, signature (6, -15, 20, -15, 6, -1).
FORMULA
G.f.: (1+6*x+x^2)*(1+60*x+134*x^2+60*x^3+x^4)/(1-x)^6.
a(n) = A008414(2*n). - Seiichi Manyama, Jun 08 2018
MATHEMATICA
Join[{1}, LinearRecurrence[{6, -15, 20, -15, 6, -1}, {72, 912, 5336, 20256, 58728, 142000}, 28]] (* Jean-François Alcover, Dec 08 2018 *)
CoefficientList[Series[(1+66 x+495 x^2+924 x^3+495 x^4+66 x^5+ x^6)/ (-1+x)^6, {x, 0, 60}], x] (* Harvey P. Dale, Jun 06 2021 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Michael Baake (mbaake(AT)sunelc3.tphys.physik.uni-tuebingen.de)
STATUS
approved