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Prime values in A067439, in the order in which they appear.
3

%I #13 Jan 19 2021 09:12:02

%S 5,19,83,89,151,167,107,71,233,163,173,359,523,317,751,569,613,587,

%T 941,823,2293,1741,1873,3541,3907,2179,7817,3907,2683,3433,6277,6577,

%U 4787,8807,9661,20051,9403,10267,23909,16927,8779,14437,14887,31231,18191,13883,14281,37987,38839,14629,22159

%N Prime values in A067439, in the order in which they appear.

%C 3907 occurs twice, as a(25) and a(28). Are there any others?

%H Robert Israel, <a href="/A340736/b340736.txt">Table of n, a(n) for n = 1..10000</a>

%F a(n) = A067439(A340731(n)).

%e a(3) = 83 because 83 = A067439(25) is the third prime value to occur in A067439.

%p f:= proc(n) local t, k;

%p t:= add(`if`(igcd(n, k)=1, n mod k, 0), k=2..n-1);

%p if isprime(t) then t fi

%p end proc:

%p map(f, [$1..1000]);

%Y Cf. A067439, A340731.

%K nonn

%O 1,1

%A _J. M. Bergot_ and _Robert Israel_, Jan 18 2021