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A034812
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Concatenation of 'prevprime(n) and n and prevprime(n)' is a prime.
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0
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5, 8, 9, 12, 14, 17, 19, 23, 25, 28, 31, 33, 38, 39, 41, 42, 47, 48, 51, 60, 61, 62, 63, 69, 71, 72, 75, 77, 78, 80, 81, 84, 85, 91, 102, 104, 105, 111, 124, 126, 149, 150, 167, 181, 182, 189, 192, 194, 215, 222, 227, 230, 233, 242, 243, 256, 271, 273, 283, 288, 308
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,1
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EXAMPLE
| n=222 -> previous prime is 211, thus '211222211' is a prime.
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MATHEMATICA
| okQ[n_] := Module[{idppn=IntegerDigits[NextPrime[n, -1]]}, PrimeQ[FromDigits[Join[idppn, IntegerDigits[n], idppn]]]]; Select[Range[350], okQ] (* From Harvey P. Dale, Jan 07 2011 *)
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CROSSREFS
| Cf. A034808-A034821.
Sequence in context: A101079 A066812 A100832 * A066467 A180244 A072833
Adjacent sequences: A034809 A034810 A034811 * A034813 A034814 A034815
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KEYWORD
| nonn,base,changed
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AUTHOR
| Patrick De Geest (pdg(AT)worldofnumbers.com), Oct 15 1998.
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