This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A031969 #31 Aug 10 2021 18:47:34 %S A031969 1023,1024,1025,1026,1027,1028,1029,1032,1034,1035,1036,1037,1038, %T A031969 1039,1042,1043,1045,1046,1047,1048,1049,1052,1053,1054,1056,1057, %U A031969 1058,1059,1062,1063,1064,1065,1067,1068,1069,1072,1073,1074,1075,1076,1078,1079,1082 %N A031969 Numbers with exactly four distinct base-10 digits. %C A031969 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 A031969 T. D. Noe, <a href="/A031969/b031969.txt">Table of n, a(n) for n = 1..4536</a> %t A031969 Select[Range[1000, 1100], Length[Union[IntegerDigits[#]]] == 4 &] (* _T. D. Noe_, Dec 04 2012 *) %o A031969 (PARI) is(n)=#Set(digits(n))==4 \\ _Charles R Greathouse IV_, Feb 11 2017 %K A031969 nonn,base %O A031969 1,1 %A A031969 _Clark Kimberling_ %E A031969 New name from _Charles R Greathouse IV_, Feb 11 2017 %E A031969 Title and finite status reverted by _Sean A. Irvine_, May 04 2020