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

 

Logo

Thanks to everyone who made a donation during our annual appeal!
To see the list of donors, or make a donation, see the OEIS Foundation home page.

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A071569 Det(M_n) where M_n is the n X n matrix m(i,j)=1 if floor(i/j) is even, 0 otherwise. 3
0, -1, 0, -2, 1, 0, -1, -3, 3, -2, 1, 1, -2, 3, -2, -6, 5, -5, 4, -2, 3, -2, 1, 3, -3, 4, -4, 6, -7, 6, -7, -9, 10, -9, 10, -10, 9, -8, 9, -5, 4, -5, 4, -2, 2, -1, 0, 8, -8, 8, -7, 9, -10, 10, -9, 13, -12, 13, -14, 12, -13, 14, -14, -18, 19, -20, 19, -17, 18, -19, 18, -18, 17, -16, 16, -14, 15 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

COMMENTS

Det(Q_n) = 1 if Q_n denotes the n X n matrix defined by: m(i,j)=1 if floor(i/j) is odd, 0 otherwise, since this matrix is triangular with 1's on the main diagonal.

LINKS

Table of n, a(n) for n=1..77.

PROG

(PARI) for(n=1, 70, print1(matdet(matrix(n, n, i, j, if((-1)^(sigma(i+j))+1, 1, 0))), ", "))

CROSSREFS

Sequence in context: A094266 A286335 A291652 * A261835 A286932 A259475

Adjacent sequences:  A071566 A071567 A071568 * A071570 A071571 A071572

KEYWORD

easy,sign

AUTHOR

Benoit Cloitre, May 30 2002

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 January 17 09:32 EST 2020. Contains 330949 sequences. (Running on oeis4.)