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Row sums of array A187360: minimal polynomials of 2*cos(Pi/n) evaluated for x=1.
2

%I #15 Oct 02 2013 19:08:41

%S 3,1,0,-1,-1,-2,-1,-1,-3,1,1,-2,1,1,-5,-1,-1,1,-1,1,7,1,1,-2,-1,1,-3,

%T 1,-1,1,-1,-1,-11,1,1,1,1,1,13,1,-1,1,-1,1,1,1,1,-2,-1,1,-17,1,-1,1,1,

%U 1,19,1,1,1,1,1,1,-1,1,1,-1,1,-23,1,1,1,1,1,-5,1,1,1,-1,1

%N Row sums of array A187360: minimal polynomials of 2*cos(Pi/n) evaluated for x=1.

%F a(n) = sum(A187360(n,m),m=0..A055034(n)), n>=1.

%F a(n) = C(n,x=1), with the minimal (monic and integer) polynomial C(n,x) of 2*cos(Pi/n).

%Y Cf. A187360, A055034, A192004.

%K sign,easy

%O 1,1

%A _Wolfdieter Lang_, Jul 14 2011