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Search: id:A080291
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| A080291 |
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a(n)=(-1)^(n+1)n^n(n+(1/12)(n^2-1)). |
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+0
1
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| 1, -9, 99, -1344, 21875, -416016, 9058973, -222298112, 6069587661, -182500000000, 5991545082831, -213243402387456, 8177627877990831, -336138206473129984, 14742427642822265625, -687141216745680797696, 33916850737339807331257
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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a(n) is the determinant of the n X n matrix M with M(i,i)=2i-n, M(i.j)=i+j.
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FORMULA
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a(n)=(-1)^(n+1)n^n(n+(1/12)(n^2-1)). a(n)=(-1)^n(n^n-n^(n-1)A002378(n)-n^(n-2)A002415(n)).
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MATHEMATICA
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Table[(-1)^(n + 1)n^n(n + (n^2 - 1)/12), {n, 1, 17}]
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CROSSREFS
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Sequence in context: A155157 A015685 A051581 this_sequence A113395 A070068 A068668
Adjacent sequences: A080288 A080289 A080290 this_sequence A080292 A080293 A080294
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KEYWORD
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easy,sign
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AUTHOR
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Mario Catalani (mario.catalani(AT)unito.it), Feb 13 2003
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