A340742 - OEIS

%I #11 Jan 19 2021 04:48:20

%S 2,2,2,7,2,7,5,7,19,13,47,31,31,17,53,41,127,79,61,113,103,229,149,73,

%T 257,383,173,613,263,293,439,541,787,883,1039,647,643,1129,1151,1181,

%U 769,1153,1303,1559,2153,2221,2393,3881,1427,1429,4211,3691,1291,3919,1549,2371,4691,4909,2251,2713,2143,4957,3863,4073,4337

%N Primes in A340740, in the order in which they occur.

%C Terms occurring more than once include 2, 7, 31, and 4073. Are there any others?

%H Robert Israel, <a href="/A340742/b340742.txt">Table of n, a(n) for n = 1..5000</a>

%F a(n) = A340740(A340741(n)).

%e a(3) = A340740(9) = 2.

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

%p   add(`if`(igcd(k, n)=1, n mod k, 0), k=1..floor(n/2))

%p end proc:

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

%Y Cf. A340736, A340740, A340741.

%K nonn

%O 1,1

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