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Search: id:A094384
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| A094384 |
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Determinant of n X n partial Hadamard matrix with coefficient m(i,j) 1<=i,j<=n (see comment). |
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+0
1
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| 1, -2, 4, 16, -32, -128, -512, 4096, -8192, -32768, -131072, 1048576, 4194304, -33554432, 268435456, 4294967296, -8589934592, -34359738368, -137438953472, 1099511627776, 4398046511104, -35184372088832, 281474976710656
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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Let M(infinity) be the infinite matrix with coefficient m(i,j) i>=1, j>=1 defined as follows : M(0)=1 and M(k) is the 2^k X 2^k matrix following the recursion : +M(k-1)-M(k-1) M(k)= -M(k-1)-M(k-1)
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FORMULA
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It appears that abs(a(n))=2^A000788(n). What is the rule for signs? Does sum(k=1, n, a(k+1)/a(k))=0 iff n is in A073536 ?
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EXAMPLE
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M(2)=/1,-1/-1,-1/ then a(2)=detM(2)=-2
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CROSSREFS
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Sequence in context: A032464 A145119 A081411 this_sequence A053038 A001088 A101926
Adjacent sequences: A094381 A094382 A094383 this_sequence A094385 A094386 A094387
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KEYWORD
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sign
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AUTHOR
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Benoit Cloitre (benoit7848c(AT)orange.fr), Jun 03 2004
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