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A186002
Hankel transform of A186001.
2
1, 1, 2, 16, 768, 294912, 1132462080, 52183852646400, 33664847019245568000, 347485857744891213250560000, 64560982045934655213753964953600000, 239901585047846581083822477336190648320000000
OFFSET
0,3
LINKS
FORMULA
a(n) = Product_{k=0..n} (2*k+0^k)^(n-k).
a(n+1) = 2^C(n+1,2)*Product_(k!,k,1,n) = A000178(n)*A006125(n+1).
Essentially the same as A108400.
From Alexander R. Povolotsky, Feb 10 2011: (Start)
WolframAlpha shows that
a(n) = (0^n*2^(1/2*(n-1)*n)*exp^(1/12-zeta^(1, 0)(-1, n+1)))/A
where zeta(s, a)is the generalized Riemann zeta function and A is the Glaisher‐Kinkelin constant.
WolframAlpha suggests that for all terms given
a(n) = 2^(1/2*(n-1)*n)*G(n+1)
where G(n) is the Barnes G-function. (End)
a(n) ~ 2^(n^2/2) * n^(n^2/2 - 1/12) * Pi^(n/2) / (A * exp(3*n^2/4 - 1/12)), where A is the Glaisher-Kinkelin constant A074962. - Vaclav Kotesovec, Feb 24 2019
MATHEMATICA
Table[2^(1/2*(n - 1)*n)*BarnesG[n + 1], {n, 0, 25}] (* G. C. Greubel, Feb 22 2017 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Paul Barry, Feb 09 2011
STATUS
approved