A071084 Determinant of the n X n matrix whose element (i,j) equals t(|i-j|) where t(n) is the number of divisors of n and t(0) = 0.

0, -1, 4, -7, 10, 68, -578, 3825, -14508, 38367, -46170, 37125, 740520, 7341147, -211529660, 2662060613, -31141230062, 234276517760, -1130151516242, 4893200552669, -6576135166508, 7495109866067, 233921918627644, 6741771472435181, -80428962094730600

Offset

1,3

Links

Iain Fox, Table of n, a(n) for n = 1..300

Mathematica

f[n_] := Det[ Table[ If[i == j, 0, DivisorSigma[0, Abs[i - j]]], {i, 1, n}, {j, 1, n}]]; Table[Abs[f[n]], {n, 1, 21}]

Prog

(PARI) a(n) = matdet(matrix(n, n, i, j, if(i == j, 0, numdiv(abs(i-j))))) \\ Iain Fox, Feb 15 2018

Crossrefs

Sequence in context: A100591 A135262 A061515 * A175833 A171964 A352583

Adjacent sequences: A071081 A071082 A071083 * A071085 A071086 A071087

Keyword

sign

Author

Robert G. Wilson v, May 26 2002

Extensions

a(22)-a(25) from Iain Fox, Feb 15 2018

Status

approved