login
This site is supported by donations to The OEIS Foundation.
Logo

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A118705 a(n) = determinant of n X n circulant matrix whose first row is the first n triangular numbers A000217(0), A000217(1), ... A000217(n-1). 1
0, -1, 28, -1360, 105500, -12051585, 1908871832, -400855203840 (list; graph; refs; listen; history; internal format)
OFFSET

1,3

LINKS

Eric Weisstein's World of Mathematics, Circulant Matrix.

FORMULA

a(n) = (-1)^(n-1)*n^(n-2)*(n+1)*(n-1)*((n+1)^n-(n-1)^n)/(6*2^n) [From Missouri State University Problem-Solving Group (MSUPSG(AT)MissouriState.edu), May 03 2010]

EXAMPLE

a(2) = - 1 because of the determinant -1 =

| 0, 1 |

| 1, 0 |.

a(4) = -1360 = determinant

|0,1,3,6|

|6,0,1,3|

|3,6,0,1|

|1,3,6,0|.

CROSSREFS

See also: A048954 Wendt determinant of n-th circulant matrix C(n). A052182 Circulant of natural numbers. A066933 Circulant of prime numbers. A086459 Circulant of powers of 2.

Cf. A000045, A048954, A052182, A066933, A086459, A086569.

Sequence in context: A092705 A061321 A091993 * A013926 A110696 A007222

Adjacent sequences:  A118702 A118703 A118704 * A118706 A118707 A118708

KEYWORD

easy,sign

AUTHOR

Jonathan Vos Post (jvospost3(AT)gmail.com), May 20 2006

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Puzzles | Hot | Classics
Recent Additions | More pages | Superseeker | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement .

Last modified February 15 08:20 EST 2012. Contains 205729 sequences.