A283796 Triangle T(n,k) read by rows: the number of symmetric q-circulant n X n {0,1}-matrices where each row and each column sum equals k.

1, 1, 1, 1, 2, 1, 1, 4, 4, 1, 1, 6, 6, 6, 1, 1, 6, 12, 12, 6, 1, 1, 8, 18, 22, 18, 8, 1, 1, 8, 24, 38, 38, 24, 8, 1, 1, 16, 38, 80, 86, 80, 38, 16, 1, 1, 10, 40, 88, 132, 132, 88, 40, 10, 1, 1, 12, 50, 128, 220, 262, 220, 128, 50, 12, 1, 1, 12, 60, 170, 340, 472, 472, 340, 170, 60, 12, 1

Offset: 0

Author

R. J. Mathar, Mar 16 2017

Keywords

• tabl
• nonn

Comments

Obtained by selecting matrices in A283795 which are symmetric, which means where the transpose of the binary matrix equals the matrix.

Is column k=1 the same as A235384?

Examples

			The matrix stars in rows n=0 and columns 0<=k<n as
1 rsum= 1
1 1 rsum= 2
1 2 1 rsum= 4
1 4 4 1 rsum= 10
1 6 6 6 1 rsum= 20
1 6 12 12 6 1 rsum= 38
1 8 18 22 18 8 1 rsum= 76
1 8 24 38 38 24 8 1 rsum= 142
1 16 38 80 86 80 38 16 1 rsum= 356
1 10 40 88 132 132 88 40 10 1 rsum= 542
1 12 50 128 220 262 220 128 50 12 1 rsum= 1084
1 12 60 170 340 472 472 340 170 60 12 1 rsum= 2110
1 24 92 282 586 936 1050 936 586 282 92 24 1 rsum= 4892
1 14 84 292 730 1302 1736 1736 1302 730 292 84 14 1 rsum= 8318
		

Crossrefs

Cf. A235384, A045655.