

A088605


a(n) is the beginning of the first set of n consecutive primes such that the concatenation of n with each of these primes is also prime.


0




OFFSET

1,1


COMMENTS

a(8) > 10^11, a(9) = 11408039.  Hans Havermann, Sep 16 2005


LINKS

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


EXAMPLE

a(3) = 7 because 7, 11 and 13 are 3 consecutive primes and 37, 311 and 313 are all prime.


MATHEMATICA

<<NumberTheory`; Do[s = 0; l = {}; While[Length[l] < n, s++; l = List[Prime[s]]; k = 1; While[k < n, p = l[[k]]; AppendTo[l, NextPrime[p]]; k++ ]; l = ToString /@ l; l = Map[ToString[n] <> #&, l]; l = ToExpression /@ l; l = Select[l, PrimeQ]]; Print[Prime[s]], {n, 1, 30}]; (* Ryan Propper, Aug 14 2005 *)


CROSSREFS

Sequence in context: A196086 A196083 A285098 * A272816 A063562 A130475
Adjacent sequences: A088602 A088603 A088604 * A088606 A088607 A088608


KEYWORD

base,hard,nonn


AUTHOR

Amarnath Murthy, Oct 15 2003


EXTENSIONS

Corrected, extended and edited by Ryan Propper and David Wasserman, Aug 14 2005
a(7) from Hans Havermann, Sep 16 2005


STATUS

approved



