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!)
A136609 (1/(n!)^2) * number of ways to arrange the consecutive numbers 1...n^2 in an n X n matrix with determinant = 0. 4
0, 0, 76, 14392910 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,3
COMMENTS
The computation of a(5) seems to be currently (Jan 2008) out of reach (compare with A088021(5)).
LINKS
EXAMPLE
a(1)=0 because det((1))/=0, a(2)=0, because the only possible determinants of a matrix with elements {1,2,3,4} are +-2, +-5 and +-10.
CROSSREFS
Cf. A001044, A046747, a(3)=A088215(0), a(4)=A136608(0), A221976.
Sequence in context: A222739 A060716 A116255 * A116246 A128670 A225522
KEYWORD
hard,more,nonn
AUTHOR
Hugo Pfoertner, Jan 21 2008
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 March 19 03:33 EDT 2024. Contains 370952 sequences. (Running on oeis4.)