%I #18 Jul 18 2020 10:31:23
%S 1,44,968,14212,156816,1388508,10286936,65652532,368804128,1854105484,
%T 8453107432,35333619428,136677756336,493244610364,1672424817272,
%U 5360494538388,16327295550016,47469373288172,132235461020168,354093052356164,913949931165392,2279318877511324,5504063080258968,12893712963761652
%N Coordination sequence for lattice D*_22 (with edges defined by l_1 norm = 1).
%H Joan Serra-Sagrista, <a href="https://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_22">Index entries for linear recurrences with constant coefficients</a>, signature (22, -231, 1540, -7315, 26334, -74613, 170544, -319770, 497420, -646646, 705432, -646646, 497420, -319770, 170544, -74613, 26334, -7315, 1540, -231, 22, -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=22.
%p C := (m, n) -> `if`(m=0,1,2^n*binomial((n+2*m)/2-1, n-1) + 2*n*hypergeom([1-m,1-n], [2], 2)): seq(simplify(C(m, 22)), m=0..21); # _Peter Luschny_, Jul 18 2020
%t n:=22; Table[Sum[2^k*Binomial[n, k]*Binomial[m-1, k-1], {k,0,n}] + 2^n*Binomial[(n+2*m)/2-1, n-1], {m,0,n+2}] (* _Georg Fischer_, Jul 18 2020 *)
%K nonn,easy
%O 0,2
%A _N. J. A. Sloane_, J. Serra-Sagrista (jserra(AT)ccd.uab.es)
%E More terms from _Georg Fischer_, Jul 18 2020