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A213318
Numbers with exactly 11 nonprime substrings (substrings with leading zeros are considered to be nonprime).
1
10037, 10103, 10111, 10117, 10123, 10127, 10130, 10134, 10136, 10138, 10151, 10153, 10157, 10159, 10163, 10167, 10171, 10172, 10175, 10191, 10192, 10195, 10199, 10213, 10217, 10227, 10229, 10231, 10232, 10235, 10239, 10243
OFFSET
1,1
COMMENTS
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 11 nonprime substrings.
The first term is a(1)=10037=A213302(11). The last term is a(32869)=82337397=A213300(11).
LINKS
EXAMPLE
a(1)= 10037, since 10037 has 11 nonprime substrings (0, 0, 1, 00, 03, 10, 003, 037, 100, 0037, 1003).
a(32869)= 82337397, since there are 11 nonprime substrings (8, 9, 33, 39, 82, 2337, 7397, 23373, 82337, 233739, 82337397).
KEYWORD
nonn,base,fini
AUTHOR
Hieronymus Fischer, Aug 26 2012
STATUS
approved