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A101302 Primes of the form Sum_{k=1..n} phi(prime(k)). 1

%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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Last modified April 16 19:48 EDT 2024. Contains 371754 sequences. (Running on oeis4.)