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A168423
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Triangle read by rows: expansion of (1 - x)/(exp(t)*(1 - x*exp(t*(1 - x))))
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0
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1, -1, 1, 1, -1, 1, -1, 1, 1, 1, 1, -1, 1, 7, 1, -1, 1, 1, 21, 21, 1, 1, -1, 1, 51, 161, 51, 1, -1, 1, 1, 113, 813, 813, 113, 1, 1, -1, 1, 239, 3361, 7631, 3361, 239, 1, -1, 1, 1, 493, 12421, 53833, 53833, 12421, 493, 1, 1, -1, 1, 1003, 42865, 320107, 607009, 320107, 42865
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OFFSET
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0,14
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COMMENTS
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This sequence was derived from the Eulerian number umbral calculus expansion and A046802 by taking the exp(t) term and inverting it.
What is interesting here is the '1,-1' terms that appear.
I had thought I would get "1,5,1" not "1,7,1" from this function.
An OEIS search came up with A046739 which has the same internal symmetric number structure.
Inverse binomial transform of Eulerian numbers A123125. [Paul Barry, May 10 2011]
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LINKS
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FORMULA
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E.g.f. sum(T(n,k) t^n/n! x^k) = p(x,t) = (1 - x)/(exp(t)*(1 - x*exp(t*(1 - x))))
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EXAMPLE
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{1},
{-1, 1},
{1, -1, 1},
{-1, 1, 1, 1},
{1, -1, 1, 7, 1},
{-1, 1, 1, 21, 21, 1},
{1, -1, 1, 51, 161, 51, 1},
{-1, 1, 1, 113, 813, 813, 113, 1},
{1, -1, 1, 239, 3361, 7631, 3361, 239, 1},
{-1, 1, 1, 493, 12421, 53833, 53833, 12421, 493, 1},
{1, -1, 1, 1003, 42865, 320107, 607009, 320107, 42865, 1003, 1}
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MATHEMATICA
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p[t_] = (1 - x)/(Exp[t]*(1 - x*Exp[t*(1 - x)]))
a = Table[ CoefficientList[FullSimplify[ExpandAll[n!*SeriesCoefficient[ Series[p[t], {t, 0, 30}], n]]], x], {n, 0, 10}];
Flatten[a]
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CROSSREFS
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KEYWORD
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AUTHOR
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STATUS
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approved
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