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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, 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
0,5
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?
EXAMPLE
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
Sequence in context: A026659 A026386 A147532 * A156580 A157528 A132731
KEYWORD
tabl,nonn
AUTHOR
R. J. Mathar, Mar 16 2017
STATUS
approved