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 A203762 a(n)=f(a(n-1),a(n-2)+1,a(n-3)), where f(x,y,z)=yz+zx+xy and (a(1),a(2),a(3))=(0,0,1). 2

%I

%S 0,0,1,1,2,8,35,403,18020,7924920,146015988543,1159796524860801383,

%T 169358027383278750824815637192,

%U 196420876345386921523978742421837032517974708496

%N a(n)=f(a(n-1),a(n-2)+1,a(n-3)), where f(x,y,z)=yz+zx+xy and (a(1),a(2),a(3))=(0,0,1).

%C For a guide to related sequences, see A203761.

%t a[1] = 0; a[2] = 0; a[3] = 1;

%t a[n_] := SymmetricPolynomial[2, {a[n - 1], 1 + a[n - 2], a[n - 3]}]

%t Table[a[n], {n, 1, 16}] (* A203762 *)

%Y Cf. A203761.

%K nonn

%O 1,5

%A _Clark Kimberling_, Jan 07 2012

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