A035798 - OEIS

%I #9 Sep 05 2023 15:06:54

%S 1,52,1352,23452,305552,3191812,27866072,209284972,1381251872,

%T 8143343572,43450388072,212064570172,955155127472,4000126870436,

%U 15677814054136,57833980313356,201820290790976,669263277244276

%N Coordination sequence for lattice D*_26 (with edges defined by l_1 norm = 1).

%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_26">Index entries for linear recurrences with constant coefficients</a>, signature (26, -325, 2600, -14950, 65780, -230230, 657800, -1562275, 3124550, -5311735, 7726160, -9657700, 10400600, -9657700, 7726160, -5311735, 3124550, -1562275, 657800, -230230, 65780, -14950, 2600, -325, 26, -1).

%F a(m)=add(2^k*binomial(n, k)*binomial(m-1, k-1), k=0..n)+2^n*binomial((n+2*m)/2-1, n-1); with n=26.

%K nonn

%O 0,2

%A _N. J. A. Sloane_, J. Serra-Sagrista (jserra(AT)ccd.uab.es)