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 A155485 #16 Mar 04 2024 01:09:34 %S A155485 1,4,20,104,540,2784,14260,72664,368780,1865744,9416100,47430024, %T A155485 238548220,1198333504,6014037140,30159664184,151156234860, %U A155485 757212830064,3791790773380,18981860359144,95000927764700,475371142699424,2378321729000820,11897472707018904 %N A155485 a(n) = 5^n + (1 - 4^n)/3. %H A155485 Vincenzo Librandi, <a href="/A155485/b155485.txt">Table of n, a(n) for n = 0..1000</a> %H A155485 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (10, -29, 20). %F A155485 a(n) = A000351(n) - A001045(2n). %F A155485 a(n) = 10a(n-1) - 29a(n-2) + 20a(n-3), as in A097165. %F A155485 From _R. J. Mathar_, Feb 27 2009: (Start) %F A155485 G.f.: (1-3x)^2/((1-x)(1-4x)(1-5x)). %F A155485 a(n) = A097165(n) - 3*A097165(n-1). (End) %o A155485 (Magma) [5^n+(1-4^n)/3: n in [0..30]]; // _Vincenzo Librandi_, Aug 07 2011 %K A155485 nonn,easy %O A155485 0,2 %A A155485 _Paul Curtz_, Jan 23 2009 %E A155485 Edited, Lava definition adopted, and extended by _R. J. Mathar_, Feb 27 2009