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 A243171 #35 Dec 16 2024 14:26:51
%S A243171 0,2,5,7,8,13,18,20,28,32,37,45,47,50,52,58,63,67,70,72,73,80,83,97,
%T A243171 98,112,117,122,125,128,130,137,145,148,158,162,163,167,175,180,182,
%U A243171 188,193,197,200,202,203,208,223,227,232,242,245,252,262,268,278,280,288,292,293,305,307,317,320,325,332,333,338,343,353,358,362,370,377,382,383
%N A243171 Nonnegative integers of the form 2*x^2+5*x*y-5*y^2.
%C A243171 Discriminant 65.
%H A243171 Vincenzo Librandi, <a href="/A243171/b243171.txt">Table of n, a(n) for n = 1..1500</a>
%H A243171 N. J. A. Sloane et al., <a href="https://oeis.org/wiki/Binary_Quadratic_Forms_and_OEIS">Binary Quadratic Forms and OEIS</a> (Index to related sequences, programs, references)
%t A243171 Module[{k,r},Reap[For[k=1,k<=100,k++,r=Reduce[k==2*x^2+5*x y-5* y^2,{x,y},Integers];If[r=!=False,(*Print[k," ",r];*)Sow[k]]]][[2,1]]] (* _Vincenzo Librandi_, Nov 16 2024 *)
%t A243171 sol[t_]:=Solve[2*x^2+5*x*y-5*y^2==t,{x,y},Integers]; Select[Range[0,385],sol[#]!={}&] (* _Vincenzo Librandi_, Nov 25 2024 *)
%Y A243171 Primes in this sequence = A141112.
%K A243171 nonn
%O A243171 1,2
%A A243171 _N. J. A. Sloane_, Jun 01 2014
%E A243171 Missing a(63)=307 inserted by _Vincenzo Librandi_, Dec 08 2024