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 A014889 #11 Apr 14 2020 13:15:24
%S A014889 761664,817499,817500,817507,817508,819609,823543,1585207,1641042,
%T A014889 1641043,1641050,1641051,1643152,1647086,2408750,2464585,2464586,
%U A014889 2464593,2464594,2466695,2470629,3232293,3288128,3288129,3288136,3288137,3290238,3294172,4055836,4111671,4111672,4111679,4111680,4113781
%N A014889 n is equal to the number of 5s in all numbers <= n written in base 7.
%H A014889 <a href="/index/Rec#order_08">Index entries for linear recurrences with constant coefficients</a>, signature (1, 0, 0, 0, 0, 0, 1, -1).
%F A014889 a(n) = a(n-1) + a(n-7) - a(n-8) for 8 < n <= 34. - _Chai Wah Wu_, Jun 06 2016
%t A014889 LinearRecurrence[{1,0,0,0,0,0,1,-1},{761664,817499,817500,817507,817508,819609,823543,1585207},34] (* _Harvey P. Dale_, Apr 14 2020 *)
%Y A014889 Cf. A014778.
%K A014889 nonn,base,fini,full
%O A014889 1,1
%A A014889 _Olivier Gérard_
%E A014889 List proved complete by _Hugo van der Sanden_ (cf. A014886).