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 A005123 #35 Feb 05 2024 00:54:55 %S A005123 2,5,9,11,12,14,17,24,29,30,32,35,39,42,44,50,51,54,56,57,65,71,72,74, %T A005123 75,77,80,84,95,96,101,107,110,116,117,119,122,126,129,131,137,141, %U A005123 144,149,150,152,156,161,162,165,170,176,179,185,186,194,200,201 %N A005123 Numbers k such that 8k + 1 is prime. %C A005123 4*a(n) is the degree of the minimal polynomial of 2*cos(Pi/A007519(n)), called C(A007519(n), x) in A187360. - _Wolfdieter Lang_, Oct 24 2013 %H A005123 T. D. Noe, <a href="/A005123/b005123.txt">Table of n, a(n) for n = 1..1000</a> %F A005123 a(n) = (A007519(n)-1)/8. - _Zak Seidov_, Sep 26 2007 %t A005123 Select[Range[0, 300], PrimeQ[8 # + 1] &] (* _Vincenzo Librandi_, Jun 25 2014 *) %o A005123 (Magma) [n: n in [0..200] | IsPrime(8*n+1)]; // _Vincenzo Librandi_, Jun 25 2014 %o A005123 (PARI) is(n)=isprime(8*n+1) \\ _Charles R Greathouse IV_, Apr 29 2015 %Y A005123 Cf. A007519, A111174, A115249. %K A005123 nonn %O A005123 1,1 %A A005123 _N. J. A. Sloane_ %E A005123 More terms from _Wesley Ivan Hurt_, Jun 25 2014