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 A083705 #30 Oct 08 2022 08:34:07 %S A083705 10,19,37,73,145,289,577,1153,2305,4609,9217,18433,36865,73729,147457, %T A083705 294913,589825,1179649,2359297,4718593,9437185,18874369,37748737, %U A083705 75497473,150994945,301989889,603979777,1207959553,2415919105,4831838209,9663676417,19327352833 %N A083705 a(n) = 2*a(n-1) - 1 with a(0) = 10. %C A083705 An Engel expansion of 2/9 to the base 2 as defined in A181565, with the associated series expansion 2/9 = 2/10 + 2^2/(10*19) + 2^3/(10*19*37) + 2^4/(10*19*37*73) + ... . - _Peter Bala_, Oct 29 2013 %H A083705 Vincenzo Librandi, <a href="/A083705/b083705.txt">Table of n, a(n) for n = 0..1000</a> %H A083705 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (3,-2). %F A083705 From _R. J. Mathar_, Aug 01 2009: (Start) %F A083705 a(n) = 1 + 9*2^n = 3*a(n-1) - 2*a(n-2). %F A083705 G.f.: -(-10+11*x)/((2*x-1)*(x-1)). (End) %F A083705 E.g.f.: exp(x)*(1 + 9*exp(x)). - _Stefano Spezia_, Oct 08 2022 %t A083705 s=10;lst={s};Do[s=s+(s-1);AppendTo[lst,s],{n,5!}];lst (* _Vladimir Joseph Stephan Orlovsky_, Nov 30 2009 *) %t A083705 NestList[2#-1&,10,40] (* _Harvey P. Dale_, Mar 13 2011 *) %o A083705 (Magma) [9*2^n+1 : n in [0..30]]; // _Vincenzo Librandi_, Nov 03 2011 %o A083705 (Python) %o A083705 from itertools import accumulate %o A083705 def f(an, _): return 2*an - 1 %o A083705 print(list(accumulate([10]*32, f))) # _Michael S. Branicky_, Oct 19 2021 %Y A083705 A020737, A083575, A083683, A083686, A168596, A181565, A195744. %K A083705 nonn,easy %O A083705 0,1 %A A083705 _N. J. A. Sloane_, Jun 15 2003