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A210638
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Iterated Rényi numbers. Square array A(n,k), n>=0, k>=0, read by antidiagonals, A(n,k) = exponential transform applied n times to the constant function -1, evaluated at k.
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1
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-1, 1, -1, 1, -1, -1, 1, -1, 0, -1, 1, -1, 1, 1, -1, 1, -1, 2, 0, 1, -1, 1, -1, 3, -4, -2, -2, -1, 1, -1, 4, -11, 8, 2, -9, -1, 1, -1, 5, -21, 49, -14, 9, -9, -1, 1, -1, 6, -34, 139, -255, 13, -24, 50, -1, 1, -1, 7, -50, 296, -1106, 1508, 45, -80, 267, -1, 1
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OFFSET
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0,18
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COMMENTS
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Motivation: The exponential transform applied n times to the constant function 1 evaluated at k was studied by E. T. Bell (Iterated Bell numbers, see A144150).
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REFERENCES
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R. E. Beard, On the coefficients in the expansion of e^e^t and e^e^(-t), J. Inst. Actuar. 76 (1950), 152-163.
Alfréd Rényi, New methods and results in combinatorial analysis. (Paper is in Hungarian.) I. MTA III Oszt. Ivozl., 16 (1966), 77-105.
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LINKS
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Antal E. Fekete, Apropos Bell and Stirling Numbers, Crux Mathematicorum with Mathematical Mayhem, Canadian Mathematical Society, Volume 25 Number 5 (May 1999), 274-281.
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EXAMPLE
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n\k [0] [1] [2] [3] [4] [5] [6]
[0] -1 -1 -1 -1 -1 -1 -1
[2] 1 -1 1 0 -2 2 9
[3] 1 -1 2 -4 8 -14 13
[4] 1 -1 3 -11 49 -255 1508
[5] 1 -1 4 -21 139 -1106 10244
[6] 1 -1 5 -34 296 -3132 38916
column3(n) = (-2+7*n-3*n^2)/2 [A115067]
column4(n) = (-2+21*n-23*n^2+6*n^3)/2
column5(n) = (-6+199*n-405*n^2+245*n^3-45*n^4)/6
column6(n) = (-24+2866*n-9213*n^2+9470*n^3-3855*n^4+540*n^5 )/24
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MAPLE
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exptr := proc(p) local g; g := proc(n) option remember; local k;
`if`(n=0, 1, add(binomial(n-1, k-1)*p(k)*g(n-k), k=1..n)) end end:
A210638 := (n, k) -> (exptr@@n)(-1)(k):
seq(lprint(seq(A210638(n, k), k=0..6)), n=0..6);
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MATHEMATICA
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exptr[p_] := Module[{g}, g[n_] := g[n] = If[n==0, 1, Sum[Binomial[n-1, k-1] p[k] g[n-k], {k, 1, n}]]; g];
A[n_, k_] := Nest[exptr, -1&, n][k];
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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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