A031969 Numbers with exactly four distinct base-10 digits.

1023, 1024, 1025, 1026, 1027, 1028, 1029, 1032, 1034, 1035, 1036, 1037, 1038, 1039, 1042, 1043, 1045, 1046, 1047, 1048, 1049, 1052, 1053, 1054, 1056, 1057, 1058, 1059, 1062, 1063, 1064, 1065, 1067, 1068, 1069, 1072, 1073, 1074, 1075, 1076, 1078, 1079, 1082

Offset: 1

Author

Clark Kimberling

Keywords

• nonn
• base

Comments

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

Links

• T. D. Noe, Table of n, a(n) for n = 1..4536

Programs

Mathematica

Select[Range[1000, 1100], Length[Union[IntegerDigits[#]]] == 4 &] (* T. D. Noe, Dec 04 2012 *)

PARI

is(n)=#Set(digits(n))==4 \\ Charles R Greathouse IV, Feb 11 2017

Extensions

New name from Charles R Greathouse IV, Feb 11 2017

Title and finite status reverted by Sean A. Irvine, May 04 2020