A203227 - OEIS

%I #22 Sep 08 2019 12:52:55

%S 1,2,5,32,780,93888,67633920,340899840000,13745206960128000,

%T 4987865758275993600000,18099969098565397826764800000,

%U 722492853172221856076141690880000000,346075232923849611911833538569175040000000000

%N (n-1)-st elementary symmetric function of (0!,...,(n-1)!)

%C Each term appears as an unreduced numerator in the following partial infinite sum: f(0) = 1; f(n) = f(n-1)/n; Sum_{k>=0}(f(k)) = e. - _Daniel Suteu_, Jul 30 2016

%C a(n)/A000178(n-1) -> e as n -> oo. - _Daniel Suteu_, Jul 30 2016

%H Alois P. Heinz, <a href="/A203227/b203227.txt">Table of n, a(n) for n = 1..44</a>

%e For n=4, the 3rd elementary symmetric polynomial in the 4 variables a, b, c, and d is abc + abd + acd + bcd. Setting a = 0! = 1, b = 1! = 1, c = 2! = 2, and d = 3! = 6 gives a(4) = 1*1*2 + 1*1*6 + 1*2*6 + 1*2*6 = 2 + 6 + 12 + 12 = 32. - _Michael B. Porter_, Aug 17 2016

%p a:= n-> coeff(mul(i!*x+1, i=0..n-1), x, n-1):

%p seq(a(n), n=1..15);  # _Alois P. Heinz_, Sep 08 2019

%t f[k_] := (k - 1)!; t[n_] := Table[f[k], {k, 1, n}]

%t a[n_] := SymmetricPolynomial[n - 1, t[n]]

%t Table[a[n], {n, 1, 14}]

%t Flatten[{1, Table[Det[Table[BellB[i+j], {i, n}, {j, n}]], {n, 1, 15}]}] (* _Vaclav Kotesovec_, Nov 28 2016 *)

%Y Cf. A203228, A000142, A000178.

%K nonn

%O 1,2

%A _Clark Kimberling_, Dec 30 2011