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Primes with an arithmetic mean of digits which is also prime.
1

%I #6 Jan 16 2013 09:27:05

%S 2,3,5,7,13,19,31,37,59,73,1061,1151,1223,1289,1487,1511,1559,1601,

%T 1667,1847,1973,1999,2099,2141,2213,2297,2411,2459,2477,2549,2657,

%U 2693,2729,2819,2837,2909,2927,2963,3023,3041,3089,3203,3221,3359,3449,3467,3539,3557

%N Primes with an arithmetic mean of digits which is also prime.

%H Harvey P. Dale, <a href="/A175762/b175762.txt">Table of n, a(n) for n = 1..1000</a>

%F {A000040(i): A007605(i)/A097944(i) in A000040}.

%e a(10)=73 because (7+3)/2=5=prime. a(12)=1151 because (1+1+5+1)/4=2=prime.

%t Select[Prime[Range[500]],PrimeQ[Mean[IntegerDigits[#]]]&] (* _Harvey P. Dale_, Jan 16 2013 *)

%Y Cf. A000040, A007605, A061383.

%K nonn,base,easy

%O 1,1

%A _Juri-Stepan Gerasimov_, Aug 29 2010

%E Corrected (59 inserted, 1061 inserted etc.) by _R. J. Mathar_, Sep 24 2010

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