A099077 - OEIS

A099077

Numbers n such that pi(1).pi(2) ... pi(n-1).pi(n) is prime (dot between numbers means concatenation).

5, 25, 2232, 4560

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OFFSET

1,1

COMMENTS

Number of digits of primes corresponding to the four known terms of this sequence are respectively 4,24,6127,13111. Next term is greater than 10250 and the prime corresponding to the next term has more than 32500 digits.

LINKS

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

Carlos Rivera, Puzzle 8. Primes by Listing, The Prime Puzzles & Problems connection.

Eric Weisstein's World of Mathematics, Integer Sequence Primes

EXAMPLE

5 is in the sequence because pi(1).pi(2).pi(3).pi(4).pi(5)=1223 is prime.

CROSSREFS

Cf. A046035, A099078, A099079, A099080.

Sequence in context: A039780 A328124 A033981 * A137113 A137115 A060063

Adjacent sequences: A099074 A099075 A099076 * A099078 A099079 A099080

KEYWORD

base,more,nonn

AUTHOR

Farideh Firoozbakht, Oct 23 2004

STATUS

approved