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%I #15 Nov 05 2021 09:41:31
%S 1,0,0,0,0,0,0,0,1,0,0,0,1,0,1,1,3,1,4,3,12,12,28,49,180,368,1901,
%T 14493,357003
%N Number of n-dimensional unimodular lattices (or quadratic forms) containing no vectors of norm 1.
%D J. H. Conway and N. J. A. Sloane, "Sphere Packings, Lattices and Groups", Springer-Verlag, p. 49.
%H Gaëtan Chenevier, <a href="https://arxiv.org/abs/2104.06846">Statistics for Kneser p-neighbors</a>, arXiv:2104.06846 [math.NT], 2021.
%H Gaëtan Chenevier, <a href="http://gaetan.chenevier.perso.math.cnrs.fr/pub.html">Publications</a>, in particular <a href="http://gaetan.chenevier.perso.math.cnrs.fr/unimodular_lattices/unimodular_lattices.gp">The rank n unimodular lattices with no norm 1 vector, for 1<=n<=27</a> and <a href="http://gaetan.chenevier.perso.math.cnrs.fr/unimodular_lattices/notice_dim28.txt">The rank 28 unimodular lattices with no norm 1 vector</a>.
%H Gaëtan Chenevier, <a href="http://gaetan.chenevier.perso.math.cnrs.fr/Unimodular_hunting_oberwolfach.pdf ">Unimodular hunting</a>, Modular Forms Workshop, Oberwolfach online, Feb 2021.
%F If 8|n then a(n) = A054908(n) + A054909(n/8), otherwise a(n) = A054908(n). - _Andrey Zabolotskiy_, Nov 05 2021
%Y Cf. A005134 (cumulative sums), A054908-A054909, A054911.
%K nonn,nice,hard
%O 0,17
%A _N. J. A. Sloane_, May 23 2000
%E a(26)-a(28) added from Gaëtan Chenevier's page by _Andrey Zabolotskiy_, Nov 05 2021
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