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 A121825 #15 Sep 08 2022 08:45:27 %S A121825 3,7,19,67,103,199,487,787,1447,2503,2707,3847,4099,4903,5479,5779, %T A121825 8467,8839,11239,12547,14887,16903,17959,19603,21319,23719,24967, %U A121825 25603,29587,31687,47527,52903,58567,59539,61507,65539,75079,81799,88807,92419 %N A121825 Duplicate of A049423. %C A121825 See also A121326 (Primes of the form 4*k^2 + 1); see also A049423 (Primes of the form k^2 + 3). For the primes of the form 4*k^2 + 3, the corresponding values of k are 1, 2, 4, 5, 7, 11, 14, 19, 25, 26, 31, 32, 35, 37, 38, 46, 47, 53, 56, 61, 65, 67, 70, 73. %F A121825 a(n) = 3 + (2*A097697(n))^2. - _R. J. Mathar_, Aug 07 2008 %o A121825 (Magma) [ a: n in [0..200] | IsPrime(a) where a is 4*n^2+3 ]; // _Vincenzo Librandi_, Dec 22 2010 %Y A121825 Cf. A000040, A002496, A049423, A121326. %K A121825 dead %O A121825 1,1 %A A121825 _Jonathan Vos Post_, Aug 27 2006 %E A121825 Terms after 21319 added by _R. J. Mathar_, Aug 07 2008 %E A121825 3 added by _Vincenzo Librandi_, Dec 22 2010