A153434 a(n) is the smallest number m such that all n numbers m+1, m.m+1, ..., m.m. ... .m+1 are prime, where dot means concatenation.

1, 2, 2, 42, 42, 1179990, 243464796

Offset

1,2

Links

Table of n, a(n) for n=1..7.

Example

All 5 numbers 1+42,1+4242,1+424242,1+42424242 & 1+4242424242 are prime and 42
is the smallest such number so a(5)=42.

Crossrefs

Cf. A153435.

Sequence in context: A116567 A215049 A087541 * A152016 A264516 A271845

Adjacent sequences: A153431 A153432 A153433 * A153435 A153436 A153437

Keyword

base,more,nonn

Author

Farideh Firoozbakht, Apr 01 2009

Status

approved