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%I #15 Jul 09 2023 02:22:45
%S 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,2,1,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,1,
%T 2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,1,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,1,
%U 2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,1,2,2,2,2,2
%N Number of distinct base-16 digits of n.
%C The first 1, 2, 3, 4,.. occur at n = 1, 16 (10_16), 258 (102_16), 4131 (1023_16), 66100 (10234_16), 1057605 (102345_16). Obviously numbers >16 appear never, so this list of records is finite. - _R. J. Mathar_, Jul 08 2023
%p A043543 := proc(n)
%p convert(convert(n,base,16),set) ;
%p nops(%) ;
%p end proc: # _R. J. Mathar_, Jul 08 2023
%t Table[Length[Union[IntegerDigits[n,16]]],{n,90}] (* _Harvey P. Dale_, Jul 23 2013 *)
%Y Differs from A297784.
%K nonn,base
%O 1,16
%A _Clark Kimberling_