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 A024142 #18 Jul 08 2025 17:28:28
%S A024142 1,11,140,1719,20720,248807,2985948,35831759,429981632,5159780271,
%T A024142 61917364124,743008370567,8916100448112,106993205378903,
%U A024142 1283918464548668,15407021574586143,184884258895036160
%N A024142 12^n-n^2.
%H A024142 Vincenzo Librandi, <a href="/A024142/b024142.txt">Table of n, a(n) for n = 0..300</a>
%H A024142 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (15,-39,37,-12).
%F A024142 G.f.: (1-4*x+14*x^2+11*x^3)/((1-12*x)*(1-x)^3). - _Vincenzo Librandi_, Oct 06 2014
%t A024142 Table[12^n - n^2, {n, 0, 25}] (* or *) CoefficientList[Series[(1 - 4 x + 14 x^2 + 11 x^3)/((1 - 12 x) (1 - x)^3), {x, 0, 30}], x] (* _Vincenzo Librandi_, Oct 06 2014 *)
%o A024142 (Magma) [12^n-n^2: n in [0..20]]; // _Vincenzo Librandi_, Jul 01 2011
%o A024142 (PARI) a(n)=12^n-n^2 \\ _Charles R Greathouse IV_, Jul 01 2011
%Y A024142 Cf. similar sequences listed in A024025.
%K A024142 nonn,easy
%O A024142 0,2
%A A024142 _N. J. A. Sloane_