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%I #11 Dec 30 2023 16:32:25
%S 3,7,13,23,149,313,619,691,769,1237,1451,4391,7639,9787,11527,19489,
%T 21943,27997,32869,35449,36107,36767,46817,49939,55691,56543,59119,
%U 61757,69127,70079,73973,81047,83117,87337,89491,91673,93871,106537
%N Primes of the form Sum_{k=1..n} phi(prime(k)).
%H Vincenzo Librandi, <a href="/A101302/b101302.txt">Table of n, a(n) for n = 1..1000</a>
%t a = {}; s = 0; Do[s = s + EulerPhi[ Prime[n]]; If[ PrimeQ[s], AppendTo[a, s]], {n, 200}]; a (* _Robert G. Wilson v_, Dec 22 2004 *)
%K nonn,easy
%O 1,1
%A _Jorge Coveiro_, Dec 22 2004
%E Edited and extended by _Robert G. Wilson v_, Dec 22 2004
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