A347015 Expansion of e.g.f. 1 / (1 + 3 * log(1 - x))^(1/3).
1, 1, 5, 42, 498, 7644, 144156, 3225648, 83536008, 2457701928, 80970232104, 2953056534768, 118112744060208, 5140622709134496, 241863782829704928, 12232551538417012992, 661818290353375962240, 38140594162828447248000, 2332567001993176540206720, 150880256846462633823648000
Offset: 0
Keywords
Links
- Seiichi Manyama, Table of n, a(n) for n = 0..372
Programs
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Maple
g:= proc(n) option remember; `if`(n<2, 1, (3*n-2)*g(n-1)) end: a:= n-> add(abs(Stirling1(n, k))*g(k), k=0..n): seq(a(n), n=0..19); # Alois P. Heinz, Aug 10 2021
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Mathematica
nmax = 19; CoefficientList[Series[1/(1 + 3 Log[1 - x])^(1/3), {x, 0, nmax}], x] Range[0, nmax]! Table[Sum[Abs[StirlingS1[n, k]] 3^k Pochhammer[1/3, k], {k, 0, n}], {n, 0, 19}]
Formula
a(n) = Sum_{k=0..n} |Stirling1(n,k)| * A007559(k).
a(n) ~ n! * exp(n/3) / (Gamma(1/3) * 3^(1/3) * n^(2/3) * (exp(1/3) - 1)^(n + 1/3)). - Vaclav Kotesovec, Aug 14 2021
a(0) = 1; a(n) = Sum_{k=1..n} (3 - 2*k/n) * (k-1)! * binomial(n,k) * a(n-k). - Seiichi Manyama, Sep 09 2023