This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A186302 #28 Jun 08 2022 03:23:30 %S A186302 3,11,15,23,35,39,51,63,75,83,95,99,111,119,131,135,155,179,183,191, %T A186302 215,219,231,239,243,251,299,303,315,323,359,363,371,375,411,419,431, %U A186302 443,455,459,483,491,495,515,519,531,543,551 %N A186302 a(n) = ( A007522(n)-1 )/2. %C A186302 From _Wolfdieter Lang_, Oct 24 2013: (Start) %C A186302 Each a(n) is of course congruent 3 (mod 4). %C A186302 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) %H A186302 Amiram Eldar, <a href="/A186302/b186302.txt">Table of n, a(n) for n = 1..10000</a> %F A186302 a(n) = A186303(n)-1. %e A186302 Degree of minimal polynomial C(prime 7 (mod 8), x): %e A186302 n = 2, p7m8(2) = A007522(2) = 23, delta(23) = 11. - _Wolfdieter Lang_, Oct 24 2013 %t A186302 (Select[8*Range[200] - 1, PrimeQ] - 1)/2 (* _Amiram Eldar_, Jun 08 2022 *) %o A186302 (PARI) is(n)=n%4==3&&isprime(2*n+1) \\ _Charles R Greathouse IV_, Jan 22 2013 %Y A186302 Cf. A007522, A055034, A186303, A187360. %K A186302 nonn,easy %O A186302 1,1 %A A186302 _Marco Matosic_, Feb 17 2011