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%I #16 Feb 24 2024 01:12:43
%S 1,3,5,15,25,75,125,375,625,1875,3125,9375,15625,46875,78125,234375,
%T 390625,1171875,1953125,5859375,9765625,29296875,48828125,146484375,
%U 244140625,732421875,1220703125,3662109375,6103515625,18310546875,30517578125
%N a(1) = 1, a(2) = 3; for n >= 3, take a(n) to be the smallest odd number not occurring earlier such that a(n-1) divides the concatenation a(n-2)a(n).
%C Apparently identical to A056487! Is this a theorem? - _Klaus Brockhaus_, Jul 21 2009
%e After 75 the term is 125 since 75 divides 25125.
%Y Cf. A111387.
%K base,nonn
%O 1,2
%A _Amarnath Murthy_, Nov 11 2005
%E More terms from _R. J. Mathar_, Aug 20 2007
%E a(21)-a(31) from _Donovan Johnson_, Apr 27 2008