A Redheffer matrix is a (0,1)-matrix that is square and has elements
equal to 1 if
or
(
divides
), and 0 otherwise. It is an integer
matrix and hence a rational matrix. For
, 2, ..., the first few Redheffer matrices
are
The Redheffer matrix of order 255 is illustrated above.
The determinant of the Redheffer matrix is equal to the Mertens
function
.
For
,
2, ..., the first few values are therefore 1, 0,
,
,
,
,
,
,
, ... (OEIS A002321).
The algebraic multiplicity of the eigenvalue 1 of the
Redheffer matrix is
for
(Vaughan 1993, p. 286; Vaughan 1996; Trott 2004, p. 57), where
denotes the binary logarithm
and
is the floor function. For
,
. The first few values for
, 2, ... are 1, 0, 1, 1, 2, 3, 4, 4, 5, 6, 7, 8, 9, 10, 11,
... (OEIS A083058).