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A118859
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Numbers n such that n-1, n+1, 2n-1, 2n+1, 3n-1 and 3n+1 are primes.
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1
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6, 53550, 420420, 422310, 1624350, 2130240, 3399900, 5199810, 5246010, 6549270, 7384440, 7775880, 9516570, 9565710, 10430280, 11845260, 13207950, 14562870, 14619990, 18747960, 20099940, 21596820, 21968100, 24358950, 24610740
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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EXAMPLE
| 6 is there because 5, 7, 11, 13, 17, 19 are all prime.
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MATHEMATICA
| tb={{0}}; Do[s1=n; s2=2*n; s3=3*n; If[(PrimeQ[n-1]&&PrimeQ[n+1])&&(PrimeQ[2*n-1]&& PrimeQ[2*n+1])&&(PrimeQ[3*n-1]&&PrimeQ[3*n+1]), Print[{s1, s2, s3}]; tb=Append[tb, n]], {n, 1, 100000000}]; tb=Delete[tb, 1]
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CROSSREFS
| Cf. A066388, A118860.
Sequence in context: A182790 A172812 A013838 * A076913 A101450 A101439
Adjacent sequences: A118856 A118857 A118858 * A118860 A118861 A118862
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KEYWORD
| nonn
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AUTHOR
| Labos E. (labos(AT)ana1.sote.hu), May 03 2006
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EXTENSIONS
| Edited by Don Reble (djr(AT)nk.ca), May 16 2006
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