%I A004026 M0862
%S A004026 1,1,1,2,3,7,33,10916
%N A004026 Number of perfect quadratic forms or lattices in dimension n.
%D A004026 J. H. Conway and N. J. A. Sloane, Low-dimensional lattices III: perfect 
               forms, Proc. Royal Soc. London, A 418 (1988), 43-80.
%D A004026 D.-O. Jaquet, Classification des reseaux dans R^7 (via la notion de formes 
               parfaites), Journees Arithmetiques, 1989 (Luminy, 1989). Asterisque 
               No. 198-200 (1991), 7-8, 177-185 (1992).
%D A004026 D.-O. Jaquet and F. Sigrist, Formes quadratiques contigues a D_7, C. 
               R. Acad. Sci. Paris Ser. I Math. 309 (1989), no. 10, 641-644.
%D A004026 J. Martinet, Les reseaux parfaits des espaces Euclidiens, Masson, Paris, 
               1996, p. 175.
%D A004026 J. Martinet, Perfect Lattices in Euclidean Spaces, Springer-Verlag, NY, 
               2003.
%D A004026 G. Nebe, Review of J. Martinet, Perfect Lattices in Euclidean Spaces, 
               Bull. Amer. Math. Soc., 41 (No. 4, 2004), 529-533.
%D A004026 M. Dutour Sikiric, A. Schuermann and F. Vallentin, Classifiaction of 
               eight-dimensional perfect forms, Preprint, 2006.
%D A004026 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, 
               Academic Press, 1995 (includes this sequence).
%H A004026 J. H. Conway and N. J. A. Sloane, <a href="http://www.research.att.com/
               ~njas/doc/splag.html">Sphere Packings, Lattices and Groups</a>, Springer-Verlag, 
               3rd edition, 1999, see Preface to 3rd Ed., especially the page that 
               was omitted by the publisher between pages xx and xxi!
%H A004026 Mathieu Dutour Sikiric, Achill Schuermann and Frank Vallentin, <a href="http:/
               /fma2.math.uni-magdeburg.de/~latgeo/perfect-forms-dim8.txt">Complete 
               list of perfect forms in dimension 8</a>
%H A004026 B. Venkov, <a href="http://www.math.u-bordeaux.fr/~martinet/">Reseaux 
               et designs spheriques</a>, pp. 10-86 in Reseaux Euclidiens, Designs 
               Spheriques et Formes Modulaires, ed. J. Martinet, L'Enseignement 
               Mathematiques, Geneva, 2001.
%Y A004026 Cf. A033689, A065535, A065536, A037075, A122079, A122080.
%Y A004026 Sequence in context: A057677 A032148 A101484 this_sequence A135907 A165744 
               A034900
%Y A004026 Adjacent sequences: A004023 A004024 A004025 this_sequence A004027 A004028 
               A004029
%K A004026 hard,nonn,nice
%O A004026 1,4
%A A004026 N. J. A. Sloane (njas(AT)research.att.com).
%E A004026 a(8) from the work of Mathieu Dutour Sikiric, Achill Schuermann and Frank 
               Vallentin, Oct 05 2005.