

A110067


Numbers n such that 10^n + sigma(n) is prime.


8




OFFSET

1,2


COMMENTS

All terms are of the form k^2 or 2*k^2. There is no further term up to 16000.
a(5) > 10^6 or it doesn't exist.  Robert Price, Mar 03 2015


LINKS

Table of n, a(n) for n=1..4.


MATHEMATICA

Do[If[PrimeQ[10^n + DivisorSigma[1, n]], Print[n]], {n, 16000}]


CROSSREFS

Cf. A110065, A110066.
Sequence in context: A018742 A255891 A018747 * A145996 A005275 A009673
Adjacent sequences: A110064 A110065 A110066 * A110068 A110069 A110070


KEYWORD

more,nonn


AUTHOR

Farideh Firoozbakht, Jul 12 2005


STATUS

approved



