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%I #9 Jul 16 2015 22:16:00
%S 103,107,111,112,115,119,122,125,129,130,134,136,138,143,147,151,152,
%T 155,159,163,170,174,176,178,183,191,192,195,199,202,203,205,207,212,
%U 215,219,220,221,224,226,228,242,245,250
%N Numbers with exactly 4 nonprime substrings (substrings with leading zeros are considered to be nonprime).
%C The sequence is finite. Proof: Each 6-digit number has at least 4 nonprime substrings, and each 4-digit number has at least 1 nonprime substring. Thus, each 10-digit number has at least 5 nonprime substrings. Consequently, there is a boundary b, such that all numbers >= b have more than 4 nonprime substrings.
%C The first term is a(1)=103=A213302(4). The last term is a(653)=373379=A213300(4).
%H Hieronymus Fischer, <a href="/A213311/b213311.txt">Table of n, a(n) for n = 1..653</a>
%e a(1) = 103, since 103 has 4 nonprime substrings (0, 03, 1, 10).
%e a(653) = 373379, since there are 4 nonprime substrings (9, 33, 3379, 7337).
%Y Cf. A019546, A035232, A039996, A046034, A069489, A085823, A211681, A211682, A211684, A211685.
%Y Cf. A035244, A079307, A213300 - A213321.
%K nonn,fini,base
%O 1,1
%A _Hieronymus Fischer_, Aug 26 2012
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