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 A213319 #7 Sep 01 2012 11:49:19 %S A213319 10023,10053,10067,10073,10079,10093,10097,10107,10112,10115,10119, %T A213319 10122,10125,10129,10141,10143,10147,10152,10155,10170,10174,10176, %U A213319 10178,10181,10183,10190,10194,10196,10198,10212,10215,10219 %N A213319 Numbers with exactly 12 nonprime substrings (substrings with leading zeros are considered to be nonprime). %C A213319 The sequence is finite. Proof: Each 9-digit number has at least 15 nonprime substrings. Thus, each number with more than 9 digits has >= 15 nonprime substrings, too. Consequently, there is a boundary b<10^9, such that all numbers > b have more than 12 nonprime substrings. %C A213319 The first term is a(1)=10023=A213302(12). The last term is a(51477)=99733313=A213300(12). %H A213319 Hieronymus Fischer, <a href="/A213319/b213319.txt">Table of n, a(n) for n = 1..51477</a> %e A213319 a(1)=10023, since 10023 has 12 nonprime substrings (0, 0, 1, 00, 02, 10, 002, 023, 100, 0023, 1002, 10023). %e A213319 a(51477)=99733313, since there are 11 nonprime substrings (1, 9, 9, 33, 33, 99, 333, 973, 33313, 97333, 733313, 99733313). %Y A213319 Cf. A019546, A035232, A039996, A046034, A069489, A085823, A211681, A211682, A211684, A211685. %Y A213319 Cf. A035244, A079307, A213300 - A213321. %K A213319 nonn,fini,base %O A213319 1,1 %A A213319 _Hieronymus Fischer_, Aug 26 2012