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 A087323 #28 Sep 08 2022 08:45:11
%S A087323 0,3,11,31,79,191,447,1023,2303,5119,11263,24575,53247,114687,245759,
%T A087323 524287,1114111,2359295,4980735,10485759,22020095,46137343,96468991,
%U A087323 201326591,419430399,872415231,1811939327,3758096383,7784628223,16106127359,33285996543,68719476735
%N A087323 a(n) = (n+1) * 2^n - 1.
%C A087323 Row sums of triangle in A018900 (without the initial 0). - _Reinhard Zumkeller_, Jun 24 2009
%H A087323 Vincenzo Librandi, <a href="/A087323/b087323.txt">Table of n, a(n) for n = 0..3000</a> (corrected by Ray Chandler, Jan 19 2019)
%H A087323 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (5,-8,4).
%F A087323 a(n) = (n + 1) * 2^n - 1 = 2^n * n + 2^n - 1.
%F A087323 a(n) = 5*a(n-1) - 8*a(n-2) + 4*a(n-3). G.f.: x*(3-4*x)/((1-x)*(1-2*x)^2). - _Colin Barker_, Mar 23 2012
%F A087323 a(n) = A001787(n+1) - 1. - _Omar E. Pol_, Nov 09 2013
%t A087323 Table[(n + 1)2^n - 1, {n, 0, 29}] (* _Alonso del Arte_, Jan 31 2014 *)
%t A087323 LinearRecurrence[{5,-8,4},{0,3,11},40] (* _Harvey P. Dale_, Sep 15 2019 *)
%o A087323 (Magma) [((n+1)*2^n - 1): n in [1..30]]; // _Vincenzo Librandi_, Sep 29 2011
%Y A087323 Cf. A087322 (a triangle which includes this sequence as the leading diagonal but without the initial zero).
%K A087323 nonn,easy
%O A087323 0,2
%A A087323 _Amarnath Murthy_, Sep 03 2003
%E A087323 Edited and extended by _David Wasserman_, May 06 2005
%E A087323 Formula promoted to definition and offset adjusted to 0 by _Alonso del Arte_, Jan 31 2014