

A046732


"Norep emirps": primes with distinct digits which remain prime when reversed.


17



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
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OFFSET

1,1


COMMENTS

There are no 10digit terms because their sum of digits would be 45 and thus the number would be divisible by 3.


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  see M. Gardner's column in Scientific American, Vol. 243, No. 6, Dec. 1980, p. 28.


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.


MAPLE

read(transforms): A046732 := proc(n) option remember: local d, k, p, distdig: if(n=1)then return 2: fi: p:=procname(n1): 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


MATHEMATICA

Select[Prime[Range[280]], Length[Union[x = IntegerDigits[#]]] == Length[x] && PrimeQ[FromDigits[Reverse[x]]] &] (* Jayanta Basu, Jun 28 2013 *)


PROG

(Python)
from sympy import prime, isprime
A046732 = [p for p in (prime(n) for n in xrange(1, 10**3)) if len(str(p)) == len(set(str(p))) and isprime(int(str(p)[::1]))] # Chai Wah Wu, Aug 14 2014


CROSSREFS

Essentially the intersection of A029743 and A006567.
Cf. A003684, A006567, A007628, A048051, A048052, A048053, A048054, A048895.
Sequence in context: A134873 A172979 A118724 * A293663 A317688 A046703
Adjacent sequences: A046729 A046730 A046731 * A046733 A046734 A046735


KEYWORD

easy,nonn,fini,full,base


AUTHOR

Enoch Haga


EXTENSIONS

More terms from Jud McCranie.


STATUS

approved



