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 A033172 #10 Aug 09 2020 17:30:40
%S A033172 365,730,1096,1461,1826,2191,2557,2922,3287,3652,4018,4383,4748,5113,
%T A033172 5479,5844,6209,6574,6940,7305,7670,8035,8401,8766,9131,9496,9862,
%U A033172 10227,10592,10957,11323,11688,12053,12418,12784,13149,13514,13879
%N A033172 Number of days in n years (n=3 is the first leap year).
%F A033172 From _Chai Wah Wu_, Jan 27 2020: (Start)
%F A033172 See caveat in A033171 formula section.
%F A033172 a(n) = a(n-1) + a(n-4) - a(n-5) for n > 5.
%F A033172 G.f.: x*(365*x^3 + 365*x^2 + 366*x + 365)/(x^5 - x^4 - x + 1). (End)
%t A033172 Accumulate[Table[If[LeapYearQ[{y,1,1}],366,365],{y,2018,2058}]] (* _Harvey P. Dale_, Aug 09 2020 *)
%Y A033172 Cf. A033171.
%K A033172 easy,nonn
%O A033172 1,1
%A A033172 _Jeff Burch_
%E A033172 a(19) corrected by _Chai Wah Wu_, Jan 27 2020