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Number of minimal polynomials of 2*cos(Pi/N) with allowed degree given by A207333.
2

%I #11 Oct 02 2013 19:16:05

%S 3,3,2,4,1,4,5,2,3,1,7,1,1,6,5,6,2,2,1,9,1,1,2,1,5,7,1,1,11,1,8,1,4,4,

%T 2,13,2,1,2,1,5,1,4,2,11,1,8,1,4,1,1,2,16,1,1,4,10

%N Number of minimal polynomials of 2*cos(Pi/N) with allowed degree given by A207333.

%C For the minimal polynomials C(N,x) of 2*cos(Pi/N) with degree delta(N) see A207333.

%F a(n) is the number of different indices N of minimal polynomials C(N,x) of 2*cos(Pi/N) with allowed degree delta(N)=A207333(n), n>=1.

%e a(8)=2 because there are exactly 2 values of N, namely 19 and 27 (see row no. 7 of the array A207334), for which the minimal polynomial C(N,x) has degree delta(N) = A207333(8) = 9.

%Y Cf. A207333, A143422.

%K nonn,easy

%O 1,1

%A _Wolfdieter Lang_, Feb 19 2012