

A178321


Numbers n such that 58/111*(10^(3n)1)1 is prime.


2



1, 2, 15, 74, 278, 541, 668, 1320, 1780, 1874, 4824, 13310, 20420, 24887
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OFFSET

1,2


COMMENTS

If n is in the sequence then m=3*(58/111*(10^(3n)1)1)) is a term of A072394.
Namely if n is a term of this sequence then for m=1/37*(58*10^(3n)169) we have sigma(m)=reversal(m)m (see comment lines of A072394).
There is no further term up to 3000. Numbers corresponding to the larger terms are probable primes.
a(15) > 50000.  Robert Price, Oct 20 2014


LINKS

Table of n, a(n) for n=1..14.


MATHEMATICA

Do[If[PrimeQ[58/111*(10^(3 n)  1)  1], Print[n]], {n, 1874}]


CROSSREFS

Cf. A072394, A178322.
Sequence in context: A056037 A125903 A268644 * A007232 A099743 A283842
Adjacent sequences: A178318 A178319 A178320 * A178322 A178323 A178324


KEYWORD

more,nonn


AUTHOR

Farideh Firoozbakht, May 26 2010


EXTENSIONS

a(11)a(14) from Robert Price, Oct 20 2014


STATUS

approved



