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 A045804 #25 Jul 09 2025 03:51:14
%S A045804 9,41,63,87,109,141,163,187,209,241,263,287,309,341,363,387,409,441,
%T A045804 463,487,509,541,563,587,609,641,663,687,709,741,763,787,809,841,863,
%U A045804 887,909,941,963,987,1009,1041,1063,1087,1109,1141,1163,1187,1209,1241
%N A045804 4-ish numbers (end in 09, 41, 63, 87).
%H A045804 Reinhard Zumkeller, <a href="/A045804/b045804.txt">Table of n, a(n) for n = 1..1000</a>
%H A045804 <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (1,0,0,1,-1).
%F A045804 G.f.: x*(9+32*x+22*x^2+24*x^3+13*x^4)/(1-x-x^4+x^5). - _Colin Barker_, Jan 23 2012
%t A045804 Select[Range[1250],MemberQ[{9,41,63,87},Mod[#,100]]&] (* _Harvey P. Dale_, Aug 01 2020 *)
%o A045804 (Haskell)
%o A045804 import Data.List (findIndices)
%o A045804 a045804 n = a045804_list !! (n-1)
%o A045804 a045804_list = findIndices (`elem` [9,41,63,87]) $ cycle [0..99]
%o A045804 -- _Reinhard Zumkeller_, Jan 23 2012
%Y A045804 Cf. A045800-A045809.
%Y A045804 Cf. A045572, A045797, A045798.
%K A045804 nonn,base,easy
%O A045804 1,1
%A A045804 _J. H. Conway_
%E A045804 More terms from _Erich Friedman_.