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A054217
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Primes p with property that p concatenated with its emirp p' (prime reversal) forms a palindromic prime of the form 'primemirp' (rightmost digit of p and leftmost digit of p' are blended together - p and p' palindromic allowed).
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5
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2, 3, 5, 7, 13, 31, 37, 79, 113, 179, 181, 199, 353, 727, 787, 907, 937, 967, 983, 1153, 1193, 1201, 1409, 1583, 1597, 1657, 1831, 1879, 3083, 3089, 3319, 3343, 3391, 3541, 3643, 3853, 7057, 7177, 7507, 7681, 7867, 7949, 9103, 9127, 9173, 9209, 9439, 9547, 9601
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OFFSET
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1,1
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COMMENTS
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LINKS
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EXAMPLE
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E.g., prime 113 has emirp 311 and 11311 is a palindromic prime, so 113 is a term.
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MATHEMATICA
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empQ[n_]:=Module[{idn=IntegerDigits[n], rev}, rev=Reverse[idn]; And@@PrimeQ[ {FromDigits[ rev], FromDigits[Join[Most[idn], rev]]}]]; Select[Prime[ Range[ 1200]], empQ] (* Harvey P. Dale, Mar 26 2013 *)
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PROG
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(Python)
from sympy import isprime
def ok(n):
if not isprime(n): return False
s = str(n); srev = s[::-1]
return isprime(int(srev)) and isprime(int(s[:-1] + srev))
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CROSSREFS
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KEYWORD
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nonn,base,nice
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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