%I #12 Aug 14 2014 03:18:41
%S 5,7,9,11,15,21,29,53,101,197,471,1205,3927,19651,137593,1243889,
%T 17815781,446377513,21886017793,2290044969551,697988552388639,
%U 733856563397342627,3102723977467356326765,72303720506476062470266309
%N a(n+1) = a(n) converted to base 7 from base 5 (written in base 10).
%H Vincenzo Librandi, <a href="/A023380/b023380.txt">Table of n, a(n) for n = 1..40</a>
%t NestList[FromDigits[IntegerDigits[#,5],7]&,5,30] (* _Harvey P. Dale_, Aug 13 2014 *)
%K nonn
%O 1,1
%A _David W. Wilson_