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A046732
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"Norep emirps": primes with distinct digits which remain prime when reversed.
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17
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2, 3, 5, 7, 13, 17, 31, 37, 71, 73, 79, 97, 107, 149, 157, 167, 179, 347, 359, 389, 701, 709, 739, 743, 751, 761, 769, 907, 937, 941, 953, 967, 971, 983, 1069, 1097, 1237, 1249, 1259, 1279, 1283, 1409, 1429, 1439, 1453, 1487, 1523, 1583, 1597, 1657, 1723, 1753
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| There are no 10-digit terms because their sum of digits would be 45 and thus the number would be divisible by 3.
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REFERENCES
| M. Gardner, column in Scientific American, Vol. 243, No. 4, September, 1980.
There are 25332 terms in this sequence, the last of which is 987653201, as found by Harvey P. Dale (hpd(AT)apscompany.com) - see M. Gardner's column in Scientific American, Vol. 243, No. 6, Dec. 1980, p. 28.
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LINKS
| Nathaniel Johnston, Table of n, a(n) for n = 1..25332 (full sequence)
C. Rivera, Commentary by Jud McCranie, The Prime Puzzles and Problems Connection.
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MAPLE
| read(transforms): A046732 := proc(n) option remember: local d, k, p, distdig: if(n=1)then return 2: fi: p:=procname(n-1): do p:=nextprime(p): if(isprime(digrev(p)))then d:=convert(p, base, 10): distdig:=true: for k from 0 to 9 do if(numboccur(d, k)>1)then distdig:=false: break: fi: od: if(distdig)then return p: fi: fi: od: end: seq(A046732(n), n=1..52); # Nathaniel Johnston, May 29 2011
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CROSSREFS
| Essentially the intersection of A029743 and A006567.
Cf. A003684, A006567, A007628, A048051, A048052, A048053, A048054, A048895.
Sequence in context: A134873 A172979 A118724 * A046703 A118722 A051026
Adjacent sequences: A046729 A046730 A046731 * A046733 A046734 A046735
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KEYWORD
| easy,nonn,fini,base
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AUTHOR
| Enoch Haga (Enokh(AT)comcast.net)
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EXTENSIONS
| More terms from Jud McCranie (JudMcCranie(AT)ugaalum.uga.edu).
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