A203232 (n-1)-st elementary symmetric function of the first n terms of the periodic sequence (2,3,2,3,2,3,...).

1, 5, 16, 60, 156, 540, 1296, 4320, 9936, 32400, 72576, 233280, 513216, 1632960, 3545856, 11197440, 24074496, 75582720, 161243136, 503884800, 1068235776, 3325639680, 7014076416, 21767823360, 45712429056, 141490851840

Offset

1,2

Links

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

Formula

Conjecture: a(n)=12*a(n-2)-36*a(n-4) with G.f. x*(1+x)*(4*x+1) / (-1+6*x^2)^2 . - R. J. Mathar, Oct 15 2013

Mathematica

r = {2, 3, 2, 3, 2, 3};
s = Flatten[{r, r, r, r, r, r, r, r, r}];
t[n_] := Part[s, Range[n]]
a[n_] := SymmetricPolynomial[n - 1, t[n]]
Table[a[n], {n, 1, 32}]     (* A203232 *)

Crossrefs

Cf. A203233.

Sequence in context: A047103 A226897 A077235 * A098347 A203414 A189450

Adjacent sequences: A203229 A203230 A203231 * A203233 A203234 A203235

Keyword

nonn

Author

Clark Kimberling, Dec 30 2011

Status

approved