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A066458
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Numbers n such that Sum_{d runs through digits of n} d^d = pi(n) (cf. A000720).
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0
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12, 22, 132, 34543, 612415, 27236725, 27236752, 311162281, 311163138, 327361548, 9237866583, 17499331217, 17499551725, 36475999489, 36475999498
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OFFSET
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1,1
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COMMENTS
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Note that only two terms, namely 34543 & 17499331217 are primes. So we have: 34543=prime(3^3+4^4+5^5+4^4+3^3), 17499331217=prime(1^1+7^7+4^4+9^9+9^9+3^3+3^3+1^1+2^2+1^1+7^7) and there is no other such prime. - Farideh Firoozbakht, Sep 23 2005
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LINKS
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Table of n, a(n) for n=1..15.
C. Caldwell and G. L. Honaker, Jr., Is pi(6521)=6!+5!+2!+1! unique?
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EXAMPLE
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a(3)=132 because there are exactly 1^1+3^3+2^2 (or 32) prime numbers less than or equal to 132.
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MATHEMATICA
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Do[ If[ Apply[Plus, IntegerDigits[n]^IntegerDigits[n]] == PrimePi[n], Print[n]], {n, 1, 10^7} ]
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CROSSREFS
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Cf. A105328, A105329.
Sequence in context: A298323 A299216 A227072 * A246342 A101104 A330212
Adjacent sequences: A066455 A066456 A066457 * A066459 A066460 A066461
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KEYWORD
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base,nonn,fini,full
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AUTHOR
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Jason Earls, Jan 02 2002
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EXTENSIONS
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More terms from Robert G. Wilson v, Jan 15 2002
Terms 27236725 onwards from Farideh Firoozbakht, Apr 21 2005 and Sep 17 2005
Sequence completed by Farideh Firoozbakht, Sep 23 2005
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STATUS
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approved
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