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 A155155 #21 Sep 08 2022 08:45:40 %S A155155 18,58,178,538,1618,4858,14578,43738,131218,393658,1180978,3542938, %T A155155 10628818,31886458,95659378,286978138,860934418,2582803258,7748409778, %U A155155 23245229338,69735688018,209207064058,627621192178,1882863576538 %N A155155 a(n) = 2*(10*3^n - 1). %H A155155 Vincenzo Librandi, <a href="/A155155/b155155.txt">Table of n, a(n) for n = 0..1000</a> %H A155155 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (4,-3). %F A155155 a(n) = 4*a(n-1) - 3*a(n-2). %F A155155 G.f.: ( 18 - 14*x ) / ( (1-x)*(1-3*x) ). %F A155155 a(n) = 10*A048473(n) + 8 = A048473(n) + A048473(n+2). %F A155155 a(n) = 3*a(n-1) - a(n-2) + 3*a(n-3) + 8. %F A155155 From _G. C. Greubel_, Mar 20 2021: (Start) %F A155155 a(n) = 18*A003462(n+1) - 14*A003462(n). %F A155155 E.g.f.: 2*( 10*exp(3*x) - exp(x) ). (End) %F A155155 a(n) = 2 * A198645(n). - _Joerg Arndt_, Mar 21 2021 %p A155155 seq(2*(10*3^n -1), n=0..30); # _G. C. Greubel_, Mar 20 2021 %t A155155 2*(10*3^Range[0,30] -1) (* _G. C. Greubel_, Mar 20 2021 *) %o A155155 (Magma) [2*(10*3^n-1): n in [0..30]]; // _Vincenzo Librandi_, Aug 07 2011 %o A155155 (Sage) [2*(10*3^n - 1) for n in (0..30)] # _G. C. Greubel_, Mar 20 2021 %Y A155155 Cf. A003462, A048473. %K A155155 nonn,easy,less %O A155155 0,1 %A A155155 _Paul Curtz_, Jan 21 2009