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 A198850 #25 Sep 17 2024 15:16:25 %S A198850 1,15,127,1023,8191,65535,524287,4194303,33554431,268435455, %T A198850 2147483647,17179869183,137438953471,1099511627775,8796093022207, %U A198850 70368744177663,562949953421311,4503599627370495,36028797018963967,288230376151711743,2305843009213693951,18446744073709551615 %N A198850 a(n) = 2*8^n - 1. %H A198850 Vincenzo Librandi, <a href="/A198850/b198850.txt">Table of n, a(n) for n = 0..1000</a> %H A198850 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (9,-8). %F A198850 a(n) = 8*a(n-1) + 7. %F A198850 a(n) = 9*a(n-1) - 8*a(n-2), n > 1. %F A198850 G.f.: (1+6*x)/((8*x-1)*(x-1)). - _R. J. Mathar_, Oct 31 2011 %F A198850 From _Elmo R. Oliveira_, Sep 13 2024: (Start) %F A198850 E.g.f.: exp(x)*(2*exp(7*x) - 1). %F A198850 a(n) = A013730(n) - 1. (End) %o A198850 (Magma) [2*8^n-1: n in [0..30]]; %Y A198850 Cf. A013730. %K A198850 nonn,easy %O A198850 0,2 %A A198850 _Vincenzo Librandi_, Oct 31 2011