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 A048490 #52 Mar 28 2024 17:25:47
%S A048490 1,9,25,57,121,249,505,1017,2041,4089,8185,16377,32761,65529,131065,
%T A048490 262137,524281,1048569,2097145,4194297,8388601,16777209,33554425,
%U A048490 67108857,134217721,268435449,536870905,1073741817,2147483641,4294967289,8589934585
%N A048490 a(n) = T(7,n), array T given by A048483.
%C A048490 n-th difference of a(n), a(n-1), ..., a(0) is (8, 8, 8, ...).
%H A048490 Colin Barker, <a href="/A048490/b048490.txt">Table of n, a(n) for n = 0..1000</a>
%H A048490 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (3,-2).
%F A048490 a(n) = 8 * 2^n - 7. - _Ralf Stephan_, Jan 09 2009
%F A048490 Equals binomial transform of [1, 8, 8, 8, ...]. - _Gary W. Adamson_, Apr 29 2008
%F A048490 a(n) = 2*a(n-1) + 7 for n > 0, a(0)=1. - _Vincenzo Librandi_, Aug 06 2010
%F A048490 For n>=1, a(n) = 6<+>(n+3), where the operation <+> is defined in A206853. - _Vladimir Shevelev_, Feb 17 2012
%F A048490 From _Colin Barker_, Nov 26 2014: (Start)
%F A048490 a(n) = 3*a(n-1) - 2*a(n-2).
%F A048490 G.f.: (6*x+1) / ((x-1)*(2*x-1)). (End)
%t A048490 a=1; lst={a}; k=8; Do[a+=k; AppendTo[lst, a]; k+=k, {n, 0, 5!}]; lst (* _Vladimir Joseph Stephan Orlovsky_, Dec 16 2008 *)
%o A048490 (PARI) Vec((6*x+1)/((x-1)*(2*x-1)) + O(x^100)) \\ _Colin Barker_, Nov 26 2014
%K A048490 nonn,easy
%O A048490 0,2
%A A048490 _Clark Kimberling_
%E A048490 More terms from _Colin Barker_, Nov 26 2014