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Search: id:A122833
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| A122833 |
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Exponential Riordan array (e^(-x(1+x)),x). |
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+0
2
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| 1, -1, 1, -1, -2, 1, 5, -3, -3, 1, 1, 20, -6, -4, 1, -41, 5, 50, -10, -5, 1, 31, -246, 15, 100, -15, -6, 1, 461, 217, -861, 35, 175, -21, -7, 1, -895, 3688, 868, -2296, 70
(list; table; graph; listen)
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OFFSET
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0,5
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COMMENT
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Inverse of A122832. Row sums are (-1)^(n/2)(1+(-1)^n)(n)!/(2(n/2)!).
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FORMULA
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Number triangle T(n,k)=(n!/k!)sum{i=0..n-k, (-1)^i*C(i,n-k-i)/i!}
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EXAMPLE
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Triangle begins
1,
-1, 1,
-1, -2, 1,
5, -3, -3, 1,
1, 20, -6, -4, 1,
-41, 5, 50, -10, -5, 1
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CROSSREFS
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Sequence in context: A106534 A123346 A163840 this_sequence A075303 A076062 A132582
Adjacent sequences: A122830 A122831 A122832 this_sequence A122834 A122835 A122836
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KEYWORD
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easy,sign,tabl
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AUTHOR
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Paul Barry (pbarry(AT)wit.ie), Sep 12 2006
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