A099083 - OEIS

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A099083

Numbers k such that 1.2. ... .k-1.k - 2 is prime (where dot between numbers means concatenation).

3

5, 31, 103, 111, 119, 201

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OFFSET

1,1

COMMENTS

Each term is odd and next term is greater than 2200.

Any further terms exceed 13000. - Lucas A. Brown, Mar 06 2024

Any further terms exceed 30000. - Michael S. Branicky, Sep 13 2024

LINKS

Table of n, a(n) for n=1..6.

EXAMPLE

31 is in the sequence because 12345678910111213141516171819202122232425262728293031 - 2 is prime.

CROSSREFS

Cf. A099081, A099082.

Sequence in context: A362304 A024399 A183520 * A212523 A096944 A053699

Adjacent sequences: A099080 A099081 A099082 * A099084 A099085 A099086

KEYWORD

base,more,nonn

AUTHOR

Farideh Firoozbakht, Nov 03 2004

STATUS

approved