cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A054908 Number of n-dimensional odd unimodular lattices (or quadratic forms) containing no vectors of norm 1.

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%I A054908 #17 Jan 25 2025 09:14:40
%S A054908 0,0,0,0,0,0,0,0,0,0,0,0,1,0,1,1,1,1,4,3,12,12,28,49,156,368,1901,
%T A054908 14493,357003
%N A054908 Number of n-dimensional odd unimodular lattices (or quadratic forms) containing no vectors of norm 1.
%D A054908 J. H. Conway and N. J. A. Sloane, "Sphere Packings, Lattices and Groups", Springer-Verlag, p. 49.
%H A054908 Bill Allombert and Gaëtan Chenevier, <a href="https://arxiv.org/abs/2410.19569">Unimodular Hunting II</a>, arXiv:2410.19569 [math.NT], 2024.
%H A054908 Gaëtan Chenevier, <a href="https://arxiv.org/abs/2410.18788">Unimodular Hunting</a>, arXiv:2410.18788 [math.NT], 2024.
%F A054908 If 8 divides n, then a(n) = A054907(n) - A054909(n/8), otherwise a(n) = A054907(n). - _Robin Visser_, Jan 24 2025
%Y A054908 Cf. A005134, A054907, A054909, A054911.
%K A054908 nonn,nice,more,hard
%O A054908 0,19
%A A054908 _N. J. A. Sloane_, May 23 2000
%E A054908 a(26)-a(28) added from Bill Allombert's and Gaëtan Chenevier's computations by _Robin Visser_, Jan 24 2025