A203155 (n-1)-st elementary symmetric function of {3, 3, 4, 4, 5, 5,..., Floor[(n+5)/2]}.

1, 6, 33, 168, 984, 5640, 37440, 246240, 1853280, 13880160, 117391680, 989936640, 9315855360, 87500528640, 907925760000, 9408462336000, 106785133056000, 1210848984576000, 14928525545472000, 183922359312384000, 2448351304261632000

Offset

1,2

Links

Table of n, a(n) for n=1..21.

Example

Let esf abbreviate "elementary symmetric function".  Then
0th esf of {3}:  1
1st esf of {3,3}:  3+3=6
2nd esf of {3,3,4} is 3*3+3*4+3*4=33

Mathematica

f[k_] := Floor[(k + 5)/2]; t[n_] := Table[f[k], {k, 1, n}]
a[n_] := SymmetricPolynomial[n - 1, t[n]]
Table[a[n], {n, 1, 22}]  (* A203155 *)

Crossrefs

Cf. A203152, A203153, A203154.

Sequence in context: A281930 A282371 A291004 * A084153 A086314 A086091

Adjacent sequences: A203152 A203153 A203154 * A203156 A203157 A203158

Keyword

nonn

Author

Clark Kimberling, Dec 29 2011

Status

approved