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A034818
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Concatenations C1 and C2 and C3 are all prime (see the comment lines).
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0
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657, 4929, 10647, 18291, 20907, 22653, 27381, 28053, 28671, 42471, 48441, 57363, 69651, 79569, 89853, 93261, 95967, 101283, 110763, 119481, 128613, 145719, 149409, 174993, 201417, 204861, 205329, 221883, 248391, 269199, 272799, 293451
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,1
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COMMENTS
| C1 = 'nextprime(n) followed by n'
C2 = 'n followed by prevprime(n)'
C3 = 'nextprime(n) followed by n followed by prevprime(n)'
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EXAMPLE
| n=95967 -> next prime is 95971, previous prime is 95959, thus '9597195967' and '9596795959' and '959719596795959' are all three primes.
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MATHEMATICA
| ccatQ[n_]:=Module[{idn=IntegerDigits[n], pp=IntegerDigits[NextPrime[n, -1]], np= IntegerDigits[ NextPrime[n]]}, And@@PrimeQ[{FromDigits[ Join[np, idn]], FromDigits[Join[idn, pp]], FromDigits[Join[np, idn, pp]]}]]; Select[ Range[300000], ccatQ] (* From Harvey P. Dale, Sep 09 2011 *)
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CROSSREFS
| Cf. A034808-A034821.
Sequence in context: A088894 A015277 A135418 * A068260 A198207 A171393
Adjacent sequences: A034815 A034816 A034817 * A034819 A034820 A034821
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KEYWORD
| nonn,base
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AUTHOR
| Patrick De Geest (pdg(AT)worldofnumbers.com), Oct 15 1998.
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