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 A198762 #21 Mar 29 2025 16:53:28
%S A198762 2,14,74,374,1874,9374,46874,234374,1171874,5859374,29296874,
%T A198762 146484374,732421874,3662109374,18310546874,91552734374,457763671874,
%U A198762 2288818359374,11444091796874,57220458984374,286102294921874,1430511474609374,7152557373046874,35762786865234374
%N A198762 a(n) = 3*5^n - 1 = 2*A057651(n).
%H A198762 Vincenzo Librandi, <a href="/A198762/b198762.txt">Table of n, a(n) for n = 0..1000</a>
%H A198762 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (6,-5).
%F A198762 a(n) = 5*a(n-1) + 4.
%F A198762 a(n) = 6*a(n-1) - 5*a(n-2), n > 1.
%F A198762 G.f.: 2*(1 + x)/(1 - 6*x + 5*x^2). - _Vincenzo Librandi_, Jan 04 2013
%F A198762 E.g.f.: exp(x)*(3*exp(4*x) - 1). - _Elmo R. Oliveira_, Mar 29 2025
%t A198762 CoefficientList[Series[2*(1 + x)/(1 - 6*x + 5*x^2), {x, 0, 30}], x] (* _Vincenzo Librandi_, Jan 04 2013 *)
%t A198762 LinearRecurrence[{6,-5},{2,14},30] (* _Harvey P. Dale_, Mar 19 2013 *)
%o A198762 (Magma) [(3*5^n-1): n in [0..30]];
%Y A198762 Cf. A024049, A057651, A081655.
%K A198762 nonn,easy
%O A198762 0,1
%A A198762 _Vincenzo Librandi_, Oct 30 2011