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Search: id:A071569
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| A071569 |
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Det(M_n) where M_n is the n X n matrix m(i,j)=1 if floor(i/j) is even, 0 otherwise. |
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+0
4
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| 0, -1, 0, -2, 1, 0, -1, -3, 3, -2, 1, 1, -2, 3, -2, -6, 5, -5, 4, -2, 3, -2, 1, 3, -3, 4, -4, 6, -7, 6, -7, -9, 10, -9, 10, -10, 9, -8, 9, -5, 4, -5, 4, -2, 2, -1, 0, 8, -8, 8, -7, 9, -10, 10, -9, 13, -12, 13, -14, 12, -13, 14, -14, -18, 19, -20, 19, -17, 18, -19, 18, -18, 17, -16, 16, -14, 15
(list; graph; listen)
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OFFSET
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1,4
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COMMENT
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Det(Q_n) = 1 if Q_n denotes the n X n matrix defined by: m(i,j)=1 if floor(i/j) is odd, 0 otherwise, since this matrix is triangular with 1's on the main diagonal.
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PROGRAM
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(PARI) for(n=1, 70, print1(matdet(matrix(n, n, i, j, if((-1)^(sigma(i+j))+1, 1, 0))), ", "))
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CROSSREFS
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Sequence in context: A096740 A096749 A096765 this_sequence A118340 A071921 A003992
Adjacent sequences: A071566 A071567 A071568 this_sequence A071570 A071571 A071572
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KEYWORD
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easy,sign
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AUTHOR
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Benoit Cloitre (benoit7848c(AT)orange.fr), May 30 2002
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