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

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A210285 Number of 2 X 2 matrices with all elements in {0,1,...,n} and determinant floor(n/2). 2
1, 10, 7, 15, 36, 52, 65, 89, 155, 179, 153, 193, 374, 422, 287, 319, 617, 681, 584, 656, 914, 962, 639, 727, 1705, 1785, 889, 961, 1672, 1784, 1768, 1888, 2496, 2576, 1483, 1579, 3460, 3604, 1843, 1939, 4177, 4337, 3298, 3466, 3886, 3982 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,2
COMMENTS
See A210000 for a guide to related sequences.
LINKS
MATHEMATICA
a = 0; b = n; z1 = 45;
t[n_] := t[n] = Flatten[Table[w*z - x*y, {w, a, b}, {x, a, b}, {y, a, b}, {z, a, b}]]
c[n_, k_] := c[n, k] = Count[t[n], k]
Table[c[n, Floor[n/2]], {n, 0, z1}] (* A210285 *)
CROSSREFS
Cf. A210000.
Sequence in context: A016731 A324087 A068444 * A190996 A210283 A227473
KEYWORD
nonn
AUTHOR
Clark Kimberling, Mar 19 2012
STATUS
approved

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 July 22 21:11 EDT 2024. Contains 374544 sequences. (Running on oeis4.)