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A167518 Least reversible prime (A007500) which is a concatenation of n consecutive primes. 1
2, 151157, 353359367, 139149151157, 101103107109113, 704517045770459704817048770489, 97101103107109113127, 1519315199152171522715233152411525915263, 382138233833384738513853386338773881, 9319932393379341934393499371937793919397 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Here the weaker definition of A007500 is used, but all terms > 2 known so far are also Emirps in the sense of A006567 (i.e. different from their reversal), so it is sufficient to change the first term to 13 in order to have a sequence of "true" emirps.

Is it possible to prove that all terms > 2 are in A006567?

LINKS

Table of n, a(n) for n=1..10.

PROG

(PARI) for(k=1, 19, for(i=0, 1e9, isprime( eval( p=concat( vector( k, j, Str( prime( i+j )))))) & isprime(eval(concat(vecextract(Vec(p), "-1..1")))) & break); print1(p, ", "))

CROSSREFS

Cf. A030997, A167517.

Sequence in context: A003840 A122540 A324438 * A178168 A271669 A006935

Adjacent sequences:  A167515 A167516 A167517 * A167519 A167520 A167521

KEYWORD

nonn,base

AUTHOR

M. F. Hasler, Nov 10 2009

EXTENSIONS

Edited by Charles R Greathouse IV, Apr 28 2010

a(9)-a(10) from Donovan Johnson, Sep 25 2011

STATUS

approved

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Last modified May 12 13:46 EDT 2021. Contains 343823 sequences. (Running on oeis4.)