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 A154517 #23 Sep 08 2022 08:45:40
%S A154517 10,38,84,148,230,330,448,584,738,910,1100,1308,1534,1778,2040,2320,
%T A154517 2618,2934,3268,3620,3990,4378,4784,5208,5650,6110,6588,7084,7598,
%U A154517 8130,8680,9248,9834,10438,11060,11700,12358,13034,13728,14440
%N A154517 a(n) = 9*n^2 + n.
%C A154517 The identity (648*n^2 + 72*n + 1)^2 - (9*n^2 + n)*(216*n + 12)^2 = 1 can be written as A154515(n)^2 - a(n)*A154519(n)^2 = 1 (see also the second comment at A154515). - _Vincenzo Librandi_, Jan 31 2012
%H A154517 Vincenzo Librandi, <a href="/A154517/b154517.txt">Table of n, a(n) for n = 1..10000</a>
%H A154517 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (3,-3,1).
%F A154517 G.f.: x*(-10 - 8*x)/(x-1)^3. - _Vincenzo Librandi_, Jan 31 2012
%F A154517 a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3). - _Vincenzo Librandi_, Jan 31 2012
%t A154517 LinearRecurrence[{3, -3, 1}, {10, 38, 84}, 50] (* _Vincenzo Librandi_, Jan 31 2012 *)
%o A154517 (PARI) a(n)=9*n^2+n \\ _Charles R Greathouse IV_, Dec 27 2011
%o A154517 (Magma) I:=[10, 38, 84]; [n le 3 select I[n] else 3*Self(n-1)-3*Self(n-2)+1*Self(n-3): n in [1..50]]; // _Vincenzo Librandi_, Jan 31 2012
%Y A154517 Cf. A154515, A154519.
%K A154517 nonn,easy
%O A154517 1,1
%A A154517 _Vincenzo Librandi_, Jan 11 2009