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A160748
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Primes whose digits are primes and reverse is prime.
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1
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2, 3, 5, 7, 37, 73, 337, 353, 373, 727, 733, 757, 3257, 3373, 3527, 3733, 7253, 7523, 7577, 7757, 32233, 32257, 32323, 32353, 32377, 32537, 33223, 33533, 35227, 35257, 35323, 35327, 35353, 35537, 35753, 37273, 37573, 72227, 72253, 72337, 72353
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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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MAPLE
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listtoint:= proc(L) local i; add(L[i]*10^(i-1), i=1..nops(L)) end proc:
f:= proc(L) local s;
s:= listtoint(L);
if isprime(s) and isprime(listtoint(ListTools:-Reverse(L))) then s fi
end proc:
Cands:= [[3], [7]]:
A:= 2, 3, 5, 7:
for m from 2 to 6 do
Cands:= map(t -> seq([op(t), j], j=[2, 3, 5, 7]), Cands);
A:= A, op(sort(map(f, Cands)));
od:
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MATHEMATICA
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okQ[p_] := PrimeQ[IntegerReverse[p] && AllTrue[IntegerDigits[p], PrimeQ]];
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PROG
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(Magma) [p: p in PrimesUpTo(2*10^5) | Set(Intseq(p)) subset [2, 3, 5, 7] and IsPrime(Seqint(Reverse(Intseq(p))))]; // Vincenzo Librandi, Dec 04 2015
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CROSSREFS
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KEYWORD
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nonn,base
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AUTHOR
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STATUS
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approved
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