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(n-1)-st elementary symmetric function of {3, 3, 4, 4, 5, 5,..., Floor[(n+5)/2]}.
2

%I #8 Nov 28 2017 11:35:56

%S 1,6,33,168,984,5640,37440,246240,1853280,13880160,117391680,

%T 989936640,9315855360,87500528640,907925760000,9408462336000,

%U 106785133056000,1210848984576000,14928525545472000,183922359312384000,2448351304261632000

%N (n-1)-st elementary symmetric function of {3, 3, 4, 4, 5, 5,..., Floor[(n+5)/2]}.

%e Let esf abbreviate "elementary symmetric function". Then

%e 0th esf of {3}: 1

%e 1st esf of {3,3}: 3+3=6

%e 2nd esf of {3,3,4} is 3*3+3*4+3*4=33

%t f[k_] := Floor[(k + 5)/2]; t[n_] := Table[f[k], {k, 1, n}]

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

%t Table[a[n], {n, 1, 22}] (* A203155 *)

%Y Cf. A203152, A203153, A203154.

%K nonn

%O 1,2

%A _Clark Kimberling_, Dec 29 2011