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Search: id:A072274
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| A072274 |
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List of Ormiston prime pairs. |
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+0
2
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| 1913, 1931, 18379, 18397, 19013, 19031, 25013, 25031, 34613, 34631, 35617, 35671, 35879, 35897, 36979, 36997, 37379, 37397, 37813, 37831, 40013, 40031, 40213, 40231, 40639, 40693, 45613, 45631, 48091, 48109, 49279, 49297, 51613, 51631
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Given the n-th prime, it is occasionally possible to form the (n+1)th prime using the same digits in a different order. Such a pair is an Ormiston Pair.
Ormiston Pairs occur rarely but randomly. It is thought that there are infinitely many but this has not been proved. They always differ by a multiple of 18. Ormiston Triples may exist but must be very large.
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REFERENCES
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A. Edwards, AAMT magazine (The Australian Maths Teacher) in an article to be published late in 2002.
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EXAMPLE
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Although 179 and 197 are composed of the same digits, they do not form an Ormiston Pair as several other primes intervene (i.e. 181, 191, 193.)
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MATHEMATICA
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a = {1}; b = {2}; Do[b = Sort[ IntegerDigits[ Prime[n]]]; If[a == b, Print[ Prime[n - 1], ", ", Prime[n]]]; a = b, {n, 1, 10^4}]
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CROSSREFS
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Cf. A069567.
Sequence in context: A124628 A112947 A069793 this_sequence A069567 A077087 A061374
Adjacent sequences: A072271 A072272 A072273 this_sequence A072275 A072276 A072277
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KEYWORD
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base,nonn
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AUTHOR
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Andy Edwards (AndynGen(AT)aol.com), Jul 09 2002
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EXTENSIONS
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Edited and corrected by Robert G. Wilson v (rgwv(AT)rgwv.com), Jul 15 2002
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