OFFSET
0,18
COMMENTS
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).
REFERENCES
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.
LINKS
E. T. Bell, The iterated exponential integers, Ann. Math. 39(3) (1938), 539-557.
Antal E. Fekete, Apropos Bell and Stirling Numbers, Crux Mathematicorum with Mathematical Mayhem, Canadian Mathematical Society, Volume 25 Number 5 (May 1999), 274-281.
Peter Luschny, Set partitions and Bell numbers
V. R. Rao Uppuluri and J. A. Carpenter, Numbers generated by the function exp(1-e^x), Fib. Quart. 7 (1969), 437-448.
EXAMPLE
n\k [0] [1] [2] [3] [4] [5] [6]
[0] -1 -1 -1 -1 -1 -1 -1
[1] 1 -1 0 1 1 -2 -9 [A000587]
[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
MAPLE
MATHEMATICA
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];
Table[A[n-k, k], {n, 0, 10}, {k, 0, n}] (* Jean-François Alcover, Jun 29 2019 *)
CROSSREFS
KEYWORD
sign,tabl
AUTHOR
Peter Luschny, Mar 26 2012
STATUS
approved