login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A243703 Nonnegative numbers represented by the indefinite quadratic form -x^2+13xy+9y^2. 1
0, 9, 21, 31, 36, 39, 41, 45, 49, 51, 61, 81, 84, 91, 105, 119, 124, 141, 144, 155, 156, 159, 164, 169, 180, 189, 195, 196, 201, 204, 205, 221, 225, 244, 245, 251, 255, 279, 289, 291, 305, 324, 329, 336, 349, 351, 364, 369, 371, 379, 389, 401, 405, 411, 419 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Discriminant 205.

LINKS

Table of n, a(n) for n=1..55.

Will Jagy, C++ program Conway_Positive_All.cc to find all positive numbers represented by an indefinite binary quadratic form

Will Jagy, Sample output from Conway_Positive_All.cc

N. J. A. Sloane et al., Binary Quadratic Forms and OEIS (Index to related sequences, programs, references)

PROG

(C++, Jagy's program, see link)

Conway_Positive_All -1 13 9 500

CROSSREFS

Primes: A243704.

Sequence in context: A139538 A173460 A110701 * A133929 A325573 A086470

Adjacent sequences:  A243700 A243701 A243702 * A243704 A243705 A243706

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Jun 17 2014

STATUS

approved

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified June 6 11:14 EDT 2020. Contains 334827 sequences. (Running on oeis4.)