A203232 - OEIS

%I #7 Oct 15 2013 14:16:47

%S 1,5,16,60,156,540,1296,4320,9936,32400,72576,233280,513216,1632960,

%T 3545856,11197440,24074496,75582720,161243136,503884800,1068235776,

%U 3325639680,7014076416,21767823360,45712429056,141490851840

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

%F 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

%t r = {2, 3, 2, 3, 2, 3};

%t s = Flatten[{r, r, r, r, r, r, r, r, r}];

%t t[n_] := Part[s, Range[n]]

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

%t Table[a[n], {n, 1, 32}]     (* A203232 *)

%Y Cf. A203233.

%K nonn

%O 1,2

%A _Clark Kimberling_, Dec 30 2011