A391693 Number of invertible n X n Hankel matrices with entries in {0,1}.

1, 4, 19, 78, 359, 1526, 6544, 27595, 116025, 480396, 1973735, 8049327, 32661563, 131897421, 531069857

Offset

1,2

Comments

A Hankel matrix M is one where each antidiagonal has identical entries; that is, M[i,j] = M[k,l] if i+j=k+l.

Links

Table of n, a(n) for n=1..15.

Example

For n = 2 the 4 matrices with nonzero Hankel determinant are [[0,1],[1,0]], [[0,1],[1,1]], [[1,0],[0,1]], and [[1,1],[1,0]].

Crossrefs

Cf. A096390, A390669, A392574.

Sequence in context: A359087 A378499 A037681 * A156760 A320088 A122909

Adjacent sequences: A391690 A391691 A391692 * A391694 A391695 A391696

Keyword

nonn,more

Author

Jeffrey Shallit, Jan 15 2026

Extensions

a(13)-a(15) from Pontus von Brömssen, Jan 30 2026

Status

approved