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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.

A262300 Let S(n,k) denote the number formed by concatenating the decimal numbers 1,2,3,...,k, but omitting n; a(n) is the smallest k for which S(n,k) is prime, or -1 if no term in S(n,*) is prime.

Table of values

n a(n)
1 2
2 3
3 7
4 9
5 11
6 7
7 11
8 1873
9 19
10 14513
11 13
12 961

List of values

[2, 3, 7, 9, 11, 7, 11, 1873, 19, 14513, 13, 961]

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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