

A046284


Primes p such that concatenation of primes from 2 through p is a prime.


6




OFFSET

1,1


COMMENTS

"w_n = (P_1)(P_2) ... (P_n) [A019518], by which notation we mean that w_n is constructed in decimal by simple concatenation of digits [much like the Almost Natural numbers (A007376)]. For example, the first few w_n are 2, 23, 235, 2357, 235711, ... ."  Crandall and Pomerance


REFERENCES

R. Crandall and C. Pomerance, Prime Numbers: A Computational Perspective, Springer, NY, 2001; see p. 72. [The 2002 printing states incorrectly that 5441 is a term.]


LINKS

Table of n, a(n) for n=1..8.
Eric Weisstein's World of Mathematics, Consecutive Number Sequences.
Eric Weisstein's World of Mathematics, Integer Sequence Primes
Eric Weisstein's World of Mathematics, SmarandacheWellin Number


EXAMPLE

7 is a member, since 2357 is a prime.


MATHEMATICA

a = ""; Do[a = StringJoin[a, ToString[ Prime[n]]]; If[ PrimeQ[ ToExpression[a]], Print[n]], {n, 1, 1429}]


CROSSREFS

Cf. A019518, A033308, A069151. a(n) = prime(A046035(n)).
Sequence in context: A062615 A180162 A129907 * A069503 A077524 A238400
Adjacent sequences: A046281 A046282 A046283 * A046285 A046286 A046287


KEYWORD

nonn,base


AUTHOR

Patrick De Geest, Jun 15 1998


EXTENSIONS

Additional comments from Robert G. Wilson v, Sep 10 2001


STATUS

approved



