%I #40 Sep 08 2022 08:44:52
%S 0,2,32,258,1408,5890,20256,59906,157184,374274,822560,1690370,
%T 3281280,6065410,10746400,18347010,30316544,48663554,76117536,
%U 116323586,174074240,255582978,368804128,523804162,733189632
%N Number of points of L1 norm 8 in cubic lattice Z^n.
%H Vincenzo Librandi, <a href="/A035602/b035602.txt">Table of n, a(n) for n = 0..1000</a>
%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 M. Janjic and B. Petkovic, <a href="https://arxiv.org/abs/1301.4550">A Counting Function</a>, arXiv preprint arXiv:1301.4550 [math.CO], 2013. - _N. J. A. Sloane_, Feb 13 2013
%H M. Janjic, B. Petkovic, <a href="https://cs.uwaterloo.ca/journals/JIS/VOL17/Janjic/janjic45.html">A Counting Function Generalizing Binomial Coefficients and Some Other Classes of Integers</a>, J. Int. Seq. 17 (2014) # 14.3.5.
%H Joan Serra-Sagrista, <a href="https://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_09">Index entries for linear recurrences with constant coefficients</a>, signature (9,-36,84,-126,126,-84,36,-9,1).
%F a(n) = (2*n^8 + 8*7*n^6 + 4*7*11*n^4 + 8*3*11*n^2)/(5*7*9). - _Frank Ellermann_, Mar 16 2002
%F G.f.: 2*x*(1+x)^7/(1-x)^9. - _Colin Barker_, Apr 15 2012
%F a(n) = 2*A099195(n). - _R. J. Mathar_, Dec 10 2013
%p f := proc(d,m) local i; sum( 2^i*binomial(d,i)*binomial(m-1,i-1),i=1..min(d,m)); end; # n=dimension, m=norm
%t CoefficientList[Series[2*x*(1+x)^7/(1-x)^9,{x,0,30}],x] (* _Vincenzo Librandi_, Apr 24 2012 *)
%o (PARI) a(n)=2*n^2*(n^6+28*n^4+154*n^2+132)/315 \\ _Charles R Greathouse IV_, Dec 07 2011
%o (Magma) [(2*n^8+8*7*n^6+4*7*11*n^4+8*3*11*n^2)/315: n in [0..30]]; // _Vincenzo Librandi_, Apr 24 2012
%Y Cf. A035596-A035607.
%K nonn,easy
%O 0,2
%A _N. J. A. Sloane_