

A019549


Primes formed by concatenating other primes.


10



23, 37, 53, 73, 113, 137, 173, 193, 197, 211, 223, 227, 229, 233, 241, 257, 271, 277, 283, 293, 311, 313, 317, 331, 337, 347, 353, 359, 367, 373, 379, 383, 389, 397, 433, 523, 541, 547, 557, 571, 577, 593, 613, 617, 673, 677, 719, 727, 733, 743, 757, 761, 773, 797, 977
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OFFSET

1,1


REFERENCES

Sylvester Smith, "A Set of Conjectures on Smarandache Sequences", Bulletin of Pure and Applied Sciences, (Bombay, India), Vol. 15 E (No. 1), 1996, pp. 101107.


LINKS

M. F. Hasler, Table of n, a(n) for n = 1..17495


EXAMPLE

113 is member as 11 and 3 are primes.
a(12)=227 = "2"+"2"+"7" is the first term not in A105184 (restricted to concatenation of two primes). [From M. F. Hasler, Oct 15 2009]


PROG

(PARI) is_A019549(n, recurse=0)={ isprime(n) == recurse & return(recurse); for(i=1, #Str(n)1, isprime( n%10^i ) & is_A019549( n\10^i, 1) & n\10^(i1)%10 & return(1)) } [Hasler]


CROSSREFS

Cf. A105184, A152242.
Sequence in context: A051362 A034302 A057878 * A272157 A129800 A105184
Adjacent sequences: A019546 A019547 A019548 * A019550 A019551 A019552


KEYWORD

nonn,base


AUTHOR

R. Muller


STATUS

approved



