Powers of 5 written backwards and sorted.

Terms

a(0) =1a(1) =5a(2) =52a(3) =521a(4) =526a(5) =5213a(6) =52187a(7) =52651a(8) =526093a(9) =5213591a(10) =5265679a(11) =52182884a(12) =526041442a(13) =5213070221a(14) =5265153016a(15) =52187571503a(16) =521354939267a(17) =526098785251