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 A081895 #14 Sep 08 2022 08:45:09 %S A081895 1,6,30,136,579,2358,9288,35640,133893,494262,1797714,6456024, %T A081895 22930695,80660934,281309436,973599912,3346483977,11431295910, %U A081895 38828142342,131206405608,441271936971,1477621745046,4927988620080,16373939547096 %N A081895 Second binomial transform of binomial(n+3, 3). %C A081895 Binomial transform of A049612. %C A081895 2nd binomial transform of binomial(n+3, 3), A000292. %C A081895 3rd binomial transform of (1,3,3,1,0,0,0,0,...). %H A081895 G. C. Greubel, <a href="/A081895/b081895.txt">Table of n, a(n) for n = 0..1000</a> %H A081895 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (12,-54,108,-81) %F A081895 a(n) = 3^n*(n^3 + 24*n^2 + 137*n + 162)/162. %F A081895 G.f.: (1 - 2*x)^3/(1 - 3*x)^4. %F A081895 E.g.f.: (6 + 18*x + 9*x^2 + x^3)*exp(3*x)/6. - _G. C. Greubel_, Oct 18 2018 %t A081895 LinearRecurrence[{12, -54, 108, -81}, {1, 6, 30, 136}, 50] (* _G. C. Greubel_, Oct 18 2018 *) %o A081895 (PARI) x='x+O('x^30); Vec((1-2*x)^3/(1-3*x)^4) \\ _G. C. Greubel_, Oct 18 2018 %o A081895 (Magma) m:=30; R<x>:=PowerSeriesRing(Integers(), m); Coefficients(R!((1-2*x)^3/(1-3*x)^4)); // _G. C. Greubel_, Oct 18 2018 %Y A081895 Cf. A081896. %K A081895 nonn,easy %O A081895 0,2 %A A081895 _Paul Barry_, Mar 30 2003