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 A356209 #10 Sep 09 2022 02:31:06 %S A356209 2,8,18,32,41,72,98,128,162,181,242,288,313,392,421,512,514,648,722, %T A356209 761,882,968,1058,1152,1201,1301,1458,1568,1466,1741,1922,2048,2178, %U A356209 2056,2381,2592,2594,2888,2817,3121,3202,3528,3698,3872,3789,4232,4418,4608,4802,4804,5101 %N A356209 a(n) is the position of the latest occurrence of n in A133388. %F A356209 a(k) = 2*k^2 for k not in A009003. %o A356209 (Python) %o A356209 from sympy.solvers.diophantine.diophantine import diop_DN %o A356209 def A356209(n): %o A356209 for m in range(n**2<<1,0,-1): %o A356209 if n==max((a for a, b in diop_DN(-1,m)),default=0): %o A356209 return m # _Chai Wah Wu_, Sep 08 2022 %Y A356209 Cf. A000161, A001481, A009003, A356208. %K A356209 nonn %O A356209 1,1 %A A356209 _Hugo Pfoertner_, Sep 07 2022