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 A332884 #72 Mar 07 2023 11:01:14
%S A332884 19,37,53,67,79,89,97,103,107,109,109,107,103,97,89,79,67,53,37,19,-1,
%T A332884 -23,-47,-73,-101,-131,-163,-197,-233,-271,-311,-353,-397,-443,-491,
%U A332884 -541,-593,-647,-703,-761,-821,-883,-947,-1013,-1081,-1151,-1223,-1297,-1373,-1451,-1531,-1613
%N A332884 a(n) = -n^2 + 21*n - 1.
%C A332884 All the positive numbers of the form -(x^2 - 21*x + 1) are primes. Compare A335984.
%D A332884 T. Özsoy, Visualization of Prime Numbers: Twin Prime Numbers, Ozsoy Triangle and Ozsoy Series, in A. Baki, B. Güven, and M. Güler, editors, Proc. 4th International Symposium of Turkish Computer and Mathematics Education, 26-Sep 28 2019, İzmir; pages 678-688.
%H A332884 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (3,-3,1).
%F A332884 G.f.: (x^2 + 20*x - 19)/(x - 1)^3. - _Jinyuan Wang_, Jul 08 2020
%t A332884 Table[-n^2+21n-1,{n,60}] (* or *) LinearRecurrence[{3,-3,1},{19,37,53},60] (* _Harvey P. Dale_, Mar 07 2023 *)
%o A332884 (PARI) a(n)=-n^2+21*n-1 \\ _Charles R Greathouse IV_, Oct 21 2022
%Y A332884 Cf. A059425, A335984.
%K A332884 sign,easy
%O A332884 1,1
%A A332884 _Tamer Özsoy_, Jul 02 2020