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

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A085511 Determinant of the n X n matrix whose element (i,j) equals sigma(|i-j|) where sigma(n) is the sum of divisors of n and sigma(0) = 0. 2
 1, 0, -1, 6, 0, -96, 1856, -19866, 194701, -143840, -12421376, -2242688, 7161224400, -182262318208, 4419601227184, -105598371081024, 1963290383833664, -34552138617760368, 6240219707831587, 4597964531722783442, 255030441797039438464, -20656928385327220865224 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,4 LINKS Table of n, a(n) for n=0..21. MAPLE a:= n-> LinearAlgebra[Determinant](Matrix(n, (i, j)-> numtheory[sigma](abs(i-j)))): seq(a(n), n=0..21); # Alois P. Heinz, Jun 17 2021 PROG (Sage) def A085511(n) : return matrix([[0 if i==j else sigma(i-j) for j in range(n)] for i in range(n)]).determinant() # Eric M. Schmidt, May 04 2013 CROSSREFS Cf. A071084, A000203. Sequence in context: A365979 A219948 A072129 * A187525 A187696 A005212 Adjacent sequences: A085508 A085509 A085510 * A085512 A085513 A085514 KEYWORD sign AUTHOR Yuval Dekel (dekelyuval(AT)hotmail.com), Aug 19 2003 EXTENSIONS More terms from Eric M. Schmidt, May 04 2013 a(0)=1 prepended by Alois P. Heinz, Jun 17 2021 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.

Last modified September 8 13:05 EDT 2024. Contains 375753 sequences. (Running on oeis4.)