A207334 Array of indices N for which the minimal polynomial C(N,x) of 2*cos(Pi/N) has allowed degree A207335(n).
1, 2, 3, 4, 5, 6, 7, 9, 8, 10, 12, 15, 11, 13, 14, 18, 21, 16, 17, 20, 24, 30, 19, 27, 22, 25, 33, 23, 26, 28, 35, 36, 39, 42, 45, 29, 31, 32, 34, 40, 48, 51, 60, 37, 38, 54, 57, 63, 41, 44, 50, 55, 66, 75, 43, 49, 46, 69, 47, 52, 56, 65, 70, 72, 78, 84, 90, 105, 53, 81, 58, 87, 59, 61, 62, 77, 93, 99
Offset: 1
Examples
Row length l(n), degree values v(n).
l(n):=A207335(n): 3, 3, 2, 4, 1, 4, 5, 2, 3, 1, ...
v(n):=A207333(n): 1, 2, 3, 4, 5, 6, 8, 9, 10, 11, ...
n, v(n)\m 1 2 3 4 5 ...
1, 1: 1 2 3
2, 2: 4 5 6
3, 3: 7 9
4, 4: 8 10 12 15
5, 5: 11
6, 6: 13 14 18 21
7, 8: 16 17 20 24 30
8, 9: 19 27
9, 10: 22 25 33
10, 11: 23
...
a(4,2)=10 because C(10,x) has degree A207333(4)=4. In fact, C(10,x) = x^4-5*x^2+5.
The set {N:delta(N)=v(4)=4} = {8,10,12,15} (ordered increasingly). Exactly these N indices lead to degree 4
polynomials C.
Crossrefs
Cf. A032447 (array for cyclotomic polynomials with Euler's phi function as degree).
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