cp's OEIS Frontend

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.

A213318 Numbers with exactly 11 nonprime substrings (substrings with leading zeros are considered to be nonprime).

Original entry on oeis.org

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

Views

Author

Hieronymus Fischer, Aug 26 2012

Keywords

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).

Examples

			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).
		

Crossrefs