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A364068
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Triangle T(n,k) read by rows: Number of traceless binary n X n matrices with all row and column sums equal to k, 1<=k<=n.
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2
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0, 1, 0, 2, 1, 0, 9, 9, 1, 0, 44, 216, 44, 1, 0, 265, 7570, 7570, 265, 1, 0, 1854, 357435, 1975560, 357435, 1854, 1, 0, 14833, 22040361, 749649145, 749649145, 22040361, 14833, 1, 0, 133496, 1721632024
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OFFSET
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1,4
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LINKS
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FORMULA
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T(n,n)=0. (k=n would require a 1 on the diagonal)
T(n,n-1)=1. (1 at all entries but the diagonal)
T(n,n-k) = T(n,k-1). (Flip entries 0<->1 and erase diagonal) - R. J. Mathar, Jul 26 2023
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EXAMPLE
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0
1 0
2 1 0
9 9 1 0
44 216 44 1 0
265 7570 7570 265 1 0
1854 357435 1975560 357435 1854 1 0
14833 22040361 749649145
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CROSSREFS
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KEYWORD
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AUTHOR
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STATUS
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approved
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