A203245 Second elementary symmetric function of the first n terms of (1,2,3,5,8,...).

2, 11, 41, 129, 376, 1048, 2850, 7635, 20273, 53537, 140912, 370128, 970978, 2545243, 6668697, 17467233, 45743336, 119779496, 313622210, 821130915, 2149841377, 5628507841, 14735867616, 38579395104, 101002803266, 264429800363

Offset

1,1

Links

Table of n, a(n) for n=1..26.

Formula

Empirical g.f.: -x*(x^3-x^2-3*x-2) / ((x-1)*(x+1)*(x^2-3*x+1)*(x^2+x-1)). - Colin Barker, Aug 15 2014

Mathematica

f[k_] := Fibonacci[k + 1]; t[n_] := Table[f[k], {k, 1, n}]
a[n_] := SymmetricPolynomial[2, t[n]]
Table[a[n], {n, 2, 32}]  (* A203245 *)

Crossrefs

Cf. A190173.

Sequence in context: A378493 A024522 A144841 * A121244 A203574 A070778

Adjacent sequences: A203242 A203243 A203244 * A203246 A203247 A203248

Keyword

nonn

Author

Clark Kimberling, Dec 31 2011

Status

approved