

A176024


Numbers k such that the reverse concatenation of the first k integers (A000422(k)) is a prime.


4




OFFSET

1,1


COMMENTS



LINKS



EXAMPLE

a(1) is 82 since the 155digit number 828180...54321 is prime.
a(2) is 37765 since the 177719digit number 377653776437763...54321 is (a probable) prime.


CROSSREFS



KEYWORD

nonn,hard,more,base,bref


AUTHOR



EXTENSIONS



STATUS

approved



