A207335 - OEIS

A207335

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

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

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OFFSET

1,1

COMMENTS

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

LINKS

Table of n, a(n) for n=1..57.

FORMULA

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.

EXAMPLE

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.

CROSSREFS

Cf. A207333, A143422.

Sequence in context: A249803 A350833 A064655 * A049604 A247509 A106686

Adjacent sequences: A207332 A207333 A207334 * A207336 A207337 A207338

KEYWORD

nonn,easy

AUTHOR

Wolfdieter Lang, Feb 19 2012

STATUS

approved