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Search: id:A158020
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| A158020 |
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Coefficients in expansion of (-1-x)^floor(n/2)(1-x)^ceil(n/2). |
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+0
1
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| 1, 1, -1, -1, 0, 1, -1, 1, 1, -1, 1, 0, -2, 0, 1, 1, -1, -2, 2, 1, -1, -1, 0, 3, 0, -3, 0, 1, -1, 1, 0, 3, -3, -3, 3, 1, -1, 1, 0, -4, 0, 6, 0, -4, 0, 1, 1, -1, -4, 4, 6, -6, -4, 4, 1, -1, -1, 0, 5, 0, -10, 0, 10, 0, -5, 0, 1, -1, 1, 5, -5, -10, 10, 10, -10, -5, 5, 1, -1
(list; table; graph; listen)
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OFFSET
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0,13
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COMMENT
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Triangle T(n,k), 0<=k<=n, read by rows given by [1,-2,1,0,0,0,0,0,0,...] DELTA [ -1,0,1,0,0,0,0,0,0,...] where DELTA is the operator defined in A084938 .
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FORMULA
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T(n,k)=T(n-2,k-2)-T(n-2,k), T(0,0)=T(1,0)=1, T(1,1)=-1 .
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EXAMPLE
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Triangle begins : 1 ; 1,-1 ; -1,0,1 ; -1,1,1,-1 ; 1,0,-2,0,1 ; ...
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CROSSREFS
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Cf. A051160
Sequence in context: A126306 A029402 A035196 this_sequence A051160 A051159 A035697
Adjacent sequences: A158017 A158018 A158019 this_sequence A158021 A158022 A158023
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KEYWORD
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sign,tabl
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AUTHOR
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Philippe DELEHAM (kolotoko(AT)wanadoo.fr), Mar 11 2009
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