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A066458
Numbers n such that Sum_{d runs through digits of n} d^d = pi(n) (cf. A000720).
0
12, 22, 132, 34543, 612415, 27236725, 27236752, 311162281, 311163138, 327361548, 9237866583, 17499331217, 17499551725, 36475999489, 36475999498
OFFSET
1,1
COMMENTS
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
LINKS
EXAMPLE
a(3)=132 because there are exactly 1^1+3^3+2^2 (or 32) prime numbers less than or equal to 132.
MATHEMATICA
Do[ If[ Apply[Plus, IntegerDigits[n]^IntegerDigits[n]] == PrimePi[n], Print[n]], {n, 1, 10^7} ]
CROSSREFS
Sequence in context: A298323 A299216 A227072 * A246342 A101104 A330212
KEYWORD
base,nonn,fini,full
AUTHOR
Jason Earls, Jan 02 2002
EXTENSIONS
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
STATUS
approved