A263677 Irregular table read by rows, n >= 1, k >= 0: T(n,k) is the number of binary symmetric n X n matrices with k holes that are squares, where the axes of symmetry are horizontal and vertical.

1, 1, 3, 1, 3, 1, 28, 15, 11, 0, 6, 3, 30, 16, 0, 0, 3, 3

Offset: 1

Author

Kival Ngaokrajang, Oct 23 2015

Keywords

• nonn
• tabf
• more

Comments

Inspired by A258643 but the axes of symmetry are the same as in A262742. The mirror patterns and nonsquare holes are excluded.

Examples

			Irregular table begins:
n\k  0  1  2  3  4  5 ...
1    1
2    1
3    3  1
4    3  1
5   28 15 11  0  6  3
6   30 16  0  0  3  3
...
		

Links

• Kival Ngaokrajang, Illustration of initial terms

Crossrefs

Cf. A258643, A262742.