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 A266991 #19 Jan 08 2016 14:45:28 %S A266991 2,11,13,101,103,113,199,1009,1013,1021,1033,1039,1103,1117,1151,1303, %T A266991 1511,1777,10007,10037,10061,10099,10103,10111,10133,10139,10141, %U A266991 10211,10223,10243,10271,10301,10303,10313,10331,10333,10343,10399,10513,10607,11003 %N A266991 Smallest representatives of primes of distinct digital types. %C A266991 Numbers of different digital types for n-digit primes are 1,2,4,11,... %H A266991 Peter J. C. Moses, <a href="/A266991/b266991.txt">Table of n, a(n) for n = 1..5000</a> %e A266991 The first 3-digit prime is 101=a(4). %e A266991 The following 3-digit prime is 103. It does not have the same digital type as 101, since in 103 there are 3 distinct digits, but not in 101. So a(5)=103. %e A266991 The next two primes 107 and 109 belongs to type 103. %e A266991 Next consider 113. Here the first two digits are the same, but in 101 and 103 they are not. So 113 is a new type, and a(6)=113. %e A266991 It remains to find the smallest prime of form XYY. It is 199=a(7). %e A266991 Now we see that every 3-digit prime is of one of the 4 types a(4),a(5),a(6),a(7). %e A266991 Next we consider the first 4-digit number a(8)=1009, etc. %Y A266991 Cf. A264406, A266946. %K A266991 nonn,base %O A266991 1,1 %A A266991 _Vladimir Shevelev_, Jan 08 2016 %E A266991 More terms from _Peter J. C. Moses_, Jan 08 2016