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 A161757 #6 Oct 25 2018 17:20:10
%S A161757 4,8,9,13,57,88,189,217,333,616,705,1045,1281,1408,1725,2233,2856,
%T A161757 3045,3760,4257,4429,5217,5800,6765,8184,8905,9165,9928,10281,11005,
%U A161757 14193,15136,16653,17017,19800,20301,22048,23865,24973,26904,28905,29512,33117
%N A161757 a(n) = (prime(n))^2 - (nonprime(n))^2.
%H A161757 G. C. Greubel, <a href="/A161757/b161757.txt">Table of n, a(n) for n = 1..5000</a>
%F A161757 a(n) = A000040(n)^2 - A141468(n)^2 = A001248(n) - A161753(n).
%e A161757 a(1)=4-0^2=4. a(2)=9-1^2=8. a(3)=25-4^2=9. a(4)=49-6^2=13. a(5)=121-8^2=57.
%t A161757 A161753:= With[{nn = 2100}, Complement[Range[0, nn], Prime[Range[PrimePi[nn]]]]^2]; Table[Prime[n]^2 - A161753[[n]], {n, 1, 100}] (* _G. C. Greubel_, Oct 25 2018 *)
%Y A161757 Cf. A001248, A141468, A161753.
%K A161757 nonn
%O A161757 1,1
%A A161757 _Juri-Stepan Gerasimov_, Jun 18 2009
%E A161757 Definition condensed, 78 replaced by 88, 145 replaced by 217, 433 replaced by 333 etc. by _R. J. Mathar_, Jun 27 2009