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 A083590 #21 Jan 21 2023 19:37:28
%S A083590 1,5,25,125,625,3126,15630,78150,390750,1953750,9768751,48843755,
%T A083590 244218775,1221093875,6105469375,30527346876,152636734380,
%U A083590 763183671900,3815918359500,19079591797500,95397958987501,476989794937505
%N A083590 Expansion of 1/((1-5*x)*(1-x^5)).
%H A083590 Vincenzo Librandi, <a href="/A083590/b083590.txt">Table of n, a(n) for n = 0..1000</a>
%H A083590 <a href="/index/Rec#order_06">Index entries for linear recurrences with constant coefficients</a>, signature (5,0,0,0,1,-5).
%F A083590 a(n) = floor(625*(5^(n+1)+1)/3124). - _Tani Akinari_, Jul 09 2013
%t A083590 CoefficientList[Series[1/((1-5x)(1-x^5)),{x,0,40}],x] (* _Vincenzo Librandi_, Apr 04 2012 *)
%t A083590 LinearRecurrence[{5,0,0,0,1,-5},{1,5,25,125,625,3126},30] (* _Harvey P. Dale_, Jan 21 2023 *)
%o A083590 (PARI) Vec(1/(1-5*x)/(1-x^5)+O(x^99)) \\ _Charles R Greathouse IV_, Apr 04 2012
%o A083590 (Magma) [Floor(625*(5^(n+1)+1)/3124): n in [0..40]]; // _G. C. Greubel_, Oct 10 2017
%Y A083590 Cf. A083589, A033139, A000975.
%K A083590 easy,nonn
%O A083590 0,2
%A A083590 _Paul Barry_, May 02 2003