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 A152692 #17 Sep 08 2022 08:45:39
%S A152692 0,0,8,54,256,1050,3984,14406,50432,172530,580240,1926078,6328128,
%T A152692 20619690,66732176,214742070,687698944,2193154530,6968850192,
%U A152692 22073006382,69714716480,219623377050,690291036688,2165100175014
%N A152692 a(n) = n*3^n - n*2^n - n*1^n.
%H A152692 Vincenzo Librandi, <a href="/A152692/b152692.txt">Table of n, a(n) for n = 0..1000</a>
%F A152692 From _R. J. Mathar_, Dec 12 2008: (Start)
%F A152692 a(n) = (-1)^(n+1)*n*A083321(n).
%F A152692 G.f.: 2*x^2*(4-21*x+36*x^2-21*x^3)/((1-x)^2*(1-3*x)^2*(1-2*x)^2). (End)
%F A152692 E.g.f.: x*(3*exp(3*x) - 2*exp(2*x) - exp(x)). - _G. C. Greubel_, Sep 02 2018
%t A152692 Table[n(3^n-2^n-1),{n,0,30}] (* _Harvey P. Dale_, Oct 20 2013 *)
%t A152692 CoefficientList[Series[-(2 x^2 (-4 + 21 x - 36 x^2 + 21 x^3))/(-1 + 6 x - 11 x^2 + 6 x^3)^2, {x, 0, 50}], x] (* _Stefano Spezia_, Sep 04 2018 *)
%o A152692 (Magma) [n*3^n-n*2^n-n*1^n: n in [0..30]]; // _Vincenzo Librandi_, Sep 05 2011
%o A152692 (PARI) vector(30, n, n--; n*(3^n-2^n-1)) \\ _G. C. Greubel_, Sep 02 2018
%Y A152692 Cf. A152691.
%K A152692 nonn,easy
%O A152692 0,3
%A A152692 _Vladimir Joseph Stephan Orlovsky_, Dec 10 2008
%E A152692 Offset changed from 1 to 0 by _Vincenzo Librandi_, Sep 05 2011