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Numbers with exactly four distinct base-10 digits.
8

%I #31 Aug 10 2021 18:47:34

%S 1023,1024,1025,1026,1027,1028,1029,1032,1034,1035,1036,1037,1038,

%T 1039,1042,1043,1045,1046,1047,1048,1049,1052,1053,1054,1056,1057,

%U 1058,1059,1062,1063,1064,1065,1067,1068,1069,1072,1073,1074,1075,1076,1078,1079,1082

%N Numbers with exactly four distinct base-10 digits.

%C Last week's challenge on National Public Radio from listener Henry Hook of Brooklyn, N.Y.: In a few weeks something will happen that hasn't happened since 1987. What is it? Answer: A year with no repeat digits (1987, 2013). - _Jonathan Vos Post_, Dec 02 2012

%H T. D. Noe, <a href="/A031969/b031969.txt">Table of n, a(n) for n = 1..4536</a>

%t Select[Range[1000, 1100], Length[Union[IntegerDigits[#]]] == 4 &] (* _T. D. Noe_, Dec 04 2012 *)

%o (PARI) is(n)=#Set(digits(n))==4 \\ _Charles R Greathouse IV_, Feb 11 2017

%K nonn,base

%O 1,1

%A _Clark Kimberling_

%E New name from _Charles R Greathouse IV_, Feb 11 2017

%E Title and finite status reverted by _Sean A. Irvine_, May 04 2020