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Numbers n such that pi(n)=d_1^1+d_2^2+...+d_k^k where d_1 d_2 ... d_k is the decimal expansion of n.
3

%I #9 Mar 30 2012 17:37:43

%S 0,12,160,253,382,3664,4683,9285,66290,207735,390481,3748380,7884391,

%T 9136095,11187665,12690170,15008945,32067066,34152082,43470982,

%U 311506482,315458182,317195680,317583584,789530607,803190747,818360167

%N Numbers n such that pi(n)=d_1^1+d_2^2+...+d_k^k where d_1 d_2 ... d_k is the decimal expansion of n.

%C This sequence is finite and the largest term is less than 10^73.

%e 43470982 is in the sequence because pi(43470982)=4^1+3^2+4^3

%e +7^4+0^5+9^6+8^7+2^8.

%t Do[d=IntegerDigits[n];k=Length[d];If[PrimePi[n]==Sum[d[[j]]^j, {j, k}], Print[n]], {n, 0, 170000000}]

%Y Cf. A032799, A112718, A112720.

%K base,fini,nonn

%O 1,2

%A _Farideh Firoozbakht_, Sep 17 2005

%E a(21)-a(27) from _Donovan Johnson_, Nov 09 2010