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A262581 Concatenation of the numbers from 1 to n but omitting 11. 0
1, 12, 123, 1234, 12345, 123456, 1234567, 12345678, 123456789, 12345678910, 1234567891012, 123456789101213, 12345678910121314, 1234567891012131415, 123456789101213141516, 12345678910121314151617, 1234567891012131415161718, 123456789101213141516171819, 12345678910121314151617181920 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

There are only two primes among the first 98 terms, namely 123456789101213 and

1234567891012131415161718192021222324252627282930313233343536\

373839404142434445464748495051525354555657585960616263.

Does this sequence contain any other primes?

LINKS

Table of n, a(n) for n=1..19.

CROSSREFS

Cf. A007908, A262299, A262571-A262582.

See A262300 for more about this problem.

Sequence in context: A138957 A007908 A262582 * A262580 A262579 A057932

Adjacent sequences:  A262578 A262579 A262580 * A262582 A262583 A262584

KEYWORD

nonn,base

AUTHOR

N. J. A. Sloane, Sep 25 2015

STATUS

approved

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Last modified July 21 17:51 EDT 2017. Contains 289643 sequences.