The OEIS is supported by the many generous donors to the OEIS Foundation.


(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A006375 Number of reduced indefinite binary forms of determinant -n.
(Formerly M0080)

%I M0080

%S 2,1,1,3,2,1,1,2,4,2,1,2,2,1,2,5,2,2,1,3,2,1,1,3,6,2,2,2,2,2,1,3,2,2,

%T 2,7,3,1,2,4,2,2,1,2,4,1,1,4,6,3,2,3,2,2,2,3,2,2,1,4,2,1,3,8,2,2,1,3,

%U 2,2

%N Number of reduced indefinite binary forms of determinant -n.

%D J. H. Conway and N. J. A. Sloane, "Sphere Packings, Lattices and Groups", Springer-Verlag, p. 362.

%D N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

%H Nachum Dershowitz, <a href="https://cs.uwaterloo.ca/journals/JIS/VOL20/Dershowitz/dersh3.html">Touchard’s Drunkard</a>, Journal of Integer Sequences, Vol. 20 (2017), #17.1.5.

%Y Cf. A006371, A006374.

%K nonn,hard

%O 1,1

%A _N. J. A. Sloane_.

%E Corrected Apr 15 1995

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified March 25 15:30 EDT 2023. Contains 361527 sequences. (Running on oeis4.)