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 A045806 #22 Aug 20 2025 03:13:17 %S A045806 23,27,61,89,123,127,161,189,223,227,261,289,323,327,361,389,423,427, %T A045806 461,489,523,527,561,589,623,627,661,689,723,727,761,789,823,827,861, %U A045806 889,923,927,961,989,1023,1027,1061,1089,1123,1127,1161,1189,1223,1227 %N A045806 6-ish numbers (end in 23, 27, 61, 89). %H A045806 Reinhard Zumkeller, <a href="/A045806/b045806.txt">Table of n, a(n) for n = 1..1000</a> %F A045806 Empirical g.f.: x*(23+4*x+34*x^2+28*x^3+11*x^4)/(1-x-x^4+x^5). - _Colin Barker_, Jan 23 2012 %o A045806 (Haskell) %o A045806 import Data.List (findIndices) %o A045806 a045806 n = a045806_list !! (n-1) %o A045806 a045806_list = findIndices (`elem` [23,27,61,89]) $ cycle [0..99] %o A045806 -- _Reinhard Zumkeller_, Jan 23 2012 %Y A045806 Cf. A045800-A045809. %Y A045806 Cf. A045572, A045797, A045798. %K A045806 nonn,base,easy %O A045806 1,1 %A A045806 _J. H. Conway_ %E A045806 More terms from _Erich Friedman_