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A065723
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Primes p such that the decimal expansion of its base 5 conversion is also prime.
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1
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2, 3, 13, 23, 41, 71, 83, 101, 163, 191, 211, 281, 283, 311, 331, 463, 503, 571, 613, 653, 701, 743, 823, 863, 881, 983, 1091, 1213, 1231, 1283, 1301, 1373, 1381, 1423, 1471, 1493, 1531, 1543, 1621, 1741, 1783, 1861, 1873, 1931, 2063, 2203, 2213, 2221
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| In general rebase notation (Marc LeBrun): p(n) = (5) [p] (10).
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LINKS
| Harry J. Smith, Table of n, a(n) for n=1,...,1000
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EXAMPLE
| E.g. 2213{10} = 32323{5} is prime but also 32323{10}.
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MATHEMATICA
| Select[ Range[2250], PrimeQ[ # ] && PrimeQ[ FromDigits[ IntegerDigits[ #, 5]]] & ]
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PROG
| (PARI) baseE(x, b)= { local(d, e=0, f=1); while (x>0, d=x-b*(x\b); x\=b; e+=d*f; f*=10); return(e) } { n=0; for (m=1, 10^9, p=prime(m); b=baseE(p, 5); if (isprime(b), write("b065723.txt", n++, " ", p); if (n==1000, return)) ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Oct 27 2009]
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CROSSREFS
| Cf. A065720 up to A065727, A065361.
Sequence in context: A181521 A133201 A103150 * A177746 A024779 A087906
Adjacent sequences: A065720 A065721 A065722 * A065724 A065725 A065726
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KEYWORD
| nonn,base
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AUTHOR
| Patrick De Geest (pdg(AT)worldofnumbers.com), Nov 15 2001.
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