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Coordination sequence for A_23 lattice.
0

%I #16 Sep 06 2023 01:58:31

%S 1,552,76452,4756952,169447302,3956576472,66087441092,839584669992,

%T 8489857618992,70764981877592,499828461729852,3059000328006312,

%U 16519884821277962,79920498285116712,350767245201478812

%N Coordination sequence for A_23 lattice.

%H R. Bacher, P. de la Harpe and B. Venkov, <a href="http://dx.doi.org/10.1016/S0764-4442(97)83542-2">Séries de croissance et séries d'Ehrhart associées aux réseaux de racines</a>, C. R. Acad. Sci. Paris, 325 (Series 1) (1997), 1137-1142.

%H J. H. Conway and N. J. A. Sloane, Low-Dimensional Lattices VII: Coordination Sequences, Proc. Royal Soc. London, A453 (1997), 2369-2389 (<a href="http://neilsloane.com/doc/Me220.pdf">pdf</a>).

%H Joan Serra-Sagrista, <a href="http://dx.doi.org/10.1016/S0020-0190(00)00119-8">Enumeration of lattice points in l_1 norm</a>, Inf. Proc. Lett. 76 (1-2) (2000) 39-44.

%H <a href="/index/Rec#order_23">Index entries for linear recurrences with constant coefficients</a>, signature (23, -253, 1771, -8855, 33649, -100947, 245157, -490314, 817190, -1144066, 1352078, -1352078, 1144066, -817190, 490314, -245157, 100947, -33649, 8855, -1771, 253, -23, 1).

%F Sum_{d=1..23} C(24, d)*C(m/2-1, d-1)*C(23-d+m/2, m/2), where norm m is always even.

%K nonn,easy

%O 0,2

%A Joan Serra-Sagrista (jserra(AT)ccd.uab.es)