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A088092
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Palindromic primes p such that if each digit d is replaced by 10-d then the resulting palindrome is also a prime.
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1
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3, 5, 7, 181, 191, 313, 353, 383, 727, 757, 797, 919, 929, 12421, 12721, 14341, 17971, 32323, 78787, 93139, 96769, 98389, 98689, 1129211, 1145411, 1153511, 1175711, 1178711, 1183811, 1221221, 1273721, 1328231, 1486841, 1633361, 1824281
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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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181 is a member as replacing 1 by 10-1 = 9 and 8 by 10-8 =2 gives 929 which is also a prime.
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MAPLE
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R:= NULL: count:= 0:
for d from 1 by 2 while count < 100 do
m:= ceil(d/2);
for r from 0 to 9^m-1 do
L:= convert(9^m+r, base, 9)[1..m] + [1$m];
L:= [ seq(L[-i], i=1..m-1), op(L)];
x:= add(L[i]*10^(i-1), i=1..d);
if isprime(x) and isprime((10^d-1)*10/9-x) then R:= R, x; count:= count+1
fi
od od:
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CROSSREFS
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KEYWORD
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base,nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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