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%I #17 Apr 23 2020 15:33:00
%S 1,1,1,1,1,1,1,1,1,1,1,1,1,1,0,0,1,1,1,0,1,1,1,0,0,1,1,1,1,0,1,1,0,1,
%T 0,1,1,1,0,1,1,1,1,0,0,1,1,1,1,0,0,0,1,1,1,0,1,1,1,1,1,1,1,0,0,0,1,0,
%U 0,0,1,0,1,1,1,1,1,0,1,0,0,1,1,0,0,1,0,1,1,0,1,0,1,1,1,0,1,1,1,1,1,0,1,0,0,1,1,1,1,1,1,0,1,1,1,0,1,1,1,0
%N a(n) = 1 if 1+phi(n) is prime, 0 otherwise, where phi = A000010, Euler totient function.
%C Out of the first 65537 values, 26197 are 1's (indicating primes), and 39340 are 0's, indicating nonprimes.
%H Antti Karttunen, <a href="/A296079/b296079.txt">Table of n, a(n) for n = 1..65537</a>
%H <a href="/index/Ch#char_fns">Index entries for characteristic functions</a>
%F a(n) = A010051(A039649(n)) = A010051(1+A000010(n)).
%F For all n, a(n) >= A010051(n) and a(2n) >= A010051(n).
%t Table[If[PrimeQ[EulerPhi[n]+1],1,0],{n,120}] (* _Harvey P. Dale_, Apr 23 2020 *)
%o (PARI) A296079(n) = isprime(1+eulerphi(n));
%Y Characteristic function of A039698.
%Y Cf. A039689 (positions of zeros).
%Y Cf. also A296077, A296078, A296080.
%K nonn
%O 1,1
%A _Antti Karttunen_, Dec 05 2017
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