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%I
%S 1,930,216690,22583810,1338036570,51479517042,1400792169890,
%T 28618505434770,458896797950430,5976672906978410,64971574193515962,
%U 602758415976923850,4860664625733355250,34599738140887685850
%N Coordination sequence for A_30 lattice.
%D 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.
%D J. Serra-Sagrista, Enumeration of lattice points in l_1 norm, Information Processing Letters, 76, no. 1-2 (2000), 39-44.
%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 <a href="/index/Rec#order_30">Index entries for linear recurrences with constant coefficients</a>, signature (30, -435, 4060, -27405, 142506, -593775, 2035800, -5852925, 14307150, -30045015, 54627300, -86493225, 119759850, -145422675, 155117520, -145422675, 119759850, -86493225, 54627300, -30045015, 14307150, -5852925, 2035800, -593775, 142506, -27405, 4060, -435, 30, -1).
%F Sum_{d=1..30} C(31, d)*C(m/2-1, d-1)*C(30-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)
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