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 A035243 #15 Sep 03 2020 19:23:40 %S A035243 1,4,5,7,9,11,16,17,19,20,23,25,28,35,36,43,44,45,47,49,55,61,63,64, %T A035243 68,73,76,77,80,81,83,85,92,95,99,100,101,112,115,119,121,125,131,133, %U A035243 137,139,140,144,149,153,157,161,163,169,171,172,175,176,180,187,188,191,196,197,199,207,209,215,220,225,229,233,235,239,244,245,251,252,253,256 %N A035243 Positive numbers of the form x^2+xy+5y^2 (discriminant -19). %C A035243 Indices of nonzero terms in expansion of Dirichlet series Product_p (1-(Kronecker(m,p)+1)*p^(-s)+Kronecker(m,p)*p^(-2s))^(-1) for m= -19 (A035171). [amended by _Georg Fischer_, Sep 03 2020] %o A035243 (PARI) m=-19; select(x -> x, direuler(p=2,101,1/(1-(kronecker(m,p)*(X-X^2))-X)), 1) \\ Fixed by _Andrey Zabolotskiy_, Sep 03 2020 %Y A035243 Cf. A035171. %Y A035243 For primes see A106863. %K A035243 nonn %O A035243 1,2 %A A035243 _N. J. A. Sloane_ %E A035243 Edited by _N. J. A. Sloane_, Jun 01 2014