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 A035247 #13 Jul 30 2020 12:22:06
%S A035247 1,3,4,5,9,11,12,15,16,20,23,25,27,31,33,36,37,44,45,47,48,49,53,55,
%T A035247 59,60,64,67,69,71,75,80,81,89,92,93,97,99,100,103,108,111,113,115,
%U A035247 121,124,125,132,135,137,141,144,147,148,155,157,159,163,165,169,176,177,179,180,181,185,188,191,192,196,199
%N A035247 Indices of the nonzero terms in expansion of Dirichlet series Product_p (1-(Kronecker(m,p)+1)*p^(-s)+Kronecker(m,p)*p^(-2s))^(-1) for m= -11.
%t A035247 Reap[For[n = 1, n < 200, n++, r = Reduce[x^2 + x y + 3 y^2 == n, {x, y}, Integers]; If[r =!= False, Sow[n]]]][[2, 1]] (* _Jean-François Alcover_, Oct 31 2016 *)
%o A035247 (PARI) m=-11; select(x -> x, direuler(p=2,101,1/(1-(kronecker(m,p)*(X-X^2))-X)), 1) \\ Fixed by _Andrey Zabolotskiy_, Jul 30 2020
%Y A035247 Cf. A028954 (a probable duplicate). [From _R. J. Mathar_, Oct 20 2008]
%Y A035247 Cf. A035179 (the expansion itself).
%K A035247 nonn
%O A035247 1,2
%A A035247 _N. J. A. Sloane_
%E A035247 More terms from _Jean-François Alcover_, Oct 31 2016
%E A035247 Name corrected by _Andrey Zabolotskiy_, Jul 30 2020