A373915 Determinants of symmetric real {0,1}-matrices of order 9 that only occur as positive values.

89, 94, 95, 97, 98, 99, 101, 102, 105, 110, 116, 125, 144

Offset: 1

Author

Hugo Pfoertner, Jun 23 2024

Keywords

• nonn
• fini
• full

Comments

The non-occurrence of the corresponding negative determinants causes the difference A089472(9) - A118985(9) = 227 - 214 = 13.

A similar situation already occurs for 7 X 7 matrices, where the 3 determinant values -20, -24, -32 only occur with negative signs.

Links

• Hugo Pfoertner, Examples of 9 X 9 matrices with determinants = a(n).

Crossrefs

Cf. A003432, A089472, A108150, A118985.