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A316158
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Expansion of e.g.f. exp(exp(exp(x*exp(x)) - 1) - 1).
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1
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1, 1, 5, 33, 280, 2883, 34817, 481477, 7489454, 129259662, 2448516959, 50460561330, 1123192711285, 26838555204646, 684871918806173, 18580595826856937, 533846105922876855, 16187892824592956798, 516492582419620294678, 17292646954057122160416, 606075769032914504000388
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OFFSET
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0,3
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COMMENTS
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Natural numbers exponentiated thrice.
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LINKS
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M. Bernstein and N. J. A. Sloane, Some canonical sequences of integers, Linear Alg. Applications, 226-228 (1995), 57-72; erratum 320 (2000), 210. [Link to Lin. Alg. Applic. version together with omitted figures]
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MAPLE
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a:= (proc(p) local g; g:= proc(n) option remember; `if`(n=0, 1,
p(n)+add(binomial(n-1, k-1)*p(k)*g(n-k), k=1..n-1))
end end@@3)(j-> j):
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MATHEMATICA
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nmax = 20; CoefficientList[Series[Exp[Exp[Exp[x Exp[x]] - 1] - 1], {x, 0, nmax}], x] Range[0, nmax]!
b[n_] := b[n] = Sum[k^(n - k) Binomial[n, k] BellB[k], {k, n}]; a[n_] := a[n] = Sum[b[k] Binomial[n - 1, k - 1] a[n - k], {k, n}]; a[0] = 1; Table[a[n], {n, 0, 20}]
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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