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A035886 Coordination sequence for diamond structure D^+_20. (Edges defined by l_1 norm = 1.) 0


%S 1,0,800,0,107200,0,5831520,0,174074240,0,3340028320,10485760,

%T 45553842240,807403520,474040586720,22284337152,3959316509440,

%U 344876646400,27528013314080,3621204787200,163698115739072

%N Coordination sequence for diamond structure D^+_20. (Edges defined by l_1 norm = 1.)

%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>).

%p f := proc(m) local k,t1; t1 := 2^(n-1)*binomial((n+2*m)/2-1,n-1); if m mod 2 = 0 then t1 := t1+add(2^k*binomial(n,k)*binomial(m-1,k-1),k=0..n); fi; t1; end; where n=20.

%K nonn

%O 0,3

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

%E Recomputed by _N. J. A. Sloane_, Nov 27 1998

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Last modified December 7 09:15 EST 2021. Contains 349574 sequences. (Running on oeis4.)