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%I #22 Sep 14 2020 16:31:20
%S 4,9,25,15,35,33,65,51,95,161,87,217,185,123,215,329,371,177,427,335,
%T 213,511,395,581,1501,485,303,515,321,545,255,635,917,411,1529,447,
%U 1057,1099,455,1169,1211,537,1991,573,965,591,435,2743,1115,681,665
%N Smallest number w such that A051953(w) = w - phi(w) is the n-th prime.
%H Amiram Eldar, <a href="/A051961/b051961.txt">Table of n, a(n) for n = 1..10000</a>
%F A050530(a(n)) = prime(n) and a(n) is the least number with this property.
%F a(n) = A063507(A000040(n)). - _Michel Marcus_, Feb 02 2015
%e The 31st term is 255 since 255 - phi(255) = 127, the 31st prime, and no number less than 255 has this property.
%t With[{c=Table[n-EulerPhi[n],{n,4000}]},Table[Position[c,p,1,1],{p,Prime[ Range[ 60]]}]]//Flatten (* _Harvey P. Dale_, Sep 14 2020 *)
%o (PARI) a(n) = {my(k = 1); while(k - eulerphi(k) != prime(n), k++); k;} \\ _Michel Marcus_, Feb 02 2015
%Y Cf. A050530, A051953.
%K nonn
%O 1,1
%A _Labos Elemer_, Jan 05 2000
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