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 A216286 #15 Jan 25 2014 16:39:17 %S A216286 2,3,5,7,11,13,17,19,23,31,37,43,47,53,59,67,71,73,79,83,97,103,107, %T A216286 113,127,131,137,139,151,157,163,167,173,179,191,193,197,199,211,223, %U A216286 227,233,239,251,257,263,271,277,283,293,307,311,313,317,331,337,347,353,359,367,373,379,383,397,419 %N A216286 Primes which cannot be written as x^2+5*y^2, where x > 0, y > 0. %C A216286 This consists of 5 together with those primes which are not congruent to 1 or 9 (mod 20) (which are listed in A216277). - _N. J. A. Sloane_, Sep 04 2012 %D A216286 David A. Cox, Primes of the Form x^2 + n y^2, Wiley, 1989. See Eq. (1.20), p. 19 and Eq. (2.22), p. 32. - _N. J. A. Sloane_, Sep 03 2012 %Y A216286 Cf. A033205, A216277. %K A216286 nonn %O A216286 1,1 %A A216286 _V. Raman_, Sep 03 2012