Voozh

A186302

a(n) = ( A007522(n)-1 )/2.

3, 11, 15, 23, 35, 39, 51, 63, 75, 83, 95, 99, 111, 119, 131, 135, 155, 179, 183, 191, 215, 219, 231, 239, 243, 251, 299, 303, 315, 323, 359, 363, 371, 375, 411, 419, 431, 443, 455, 459, 483, 491, 495, 515, 519, 531, 543, 551

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OFFSET

1,1

COMMENTS

From Wolfdieter Lang, Oct 24 2013: (Start)

Each a(n) is of course congruent 3 (mod 4).

a(n) = A055034(p7m8(n)), with p7m8(n) := A007522(n). This is the degree of the minimal polynomial of rho(p7m8(n)):= 2*cos(Pi/p7m8(n)), called C(p7m8(n), x) in A187360. (End)

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..10000

FORMULA

a(n) = A186303(n)-1.

EXAMPLE

Degree of minimal polynomial C(prime 7 (mod 8), x):

n = 2, p7m8(2) = A007522(2) = 23, delta(23) = 11. - Wolfdieter Lang, Oct 24 2013

MATHEMATICA

(Select[8*Range[200] - 1, PrimeQ] - 1)/2 (* Amiram Eldar, Jun 08 2022 *)

PROG

(PARI) is(n)=n%4==3&&isprime(2*n+1) \\ Charles R Greathouse IV, Jan 22 2013

CROSSREFS