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%I #10 Sep 08 2022 08:45:35
%S 1,6,12,18,22,30,36,42,46,52,60,66,72,78,82,88,96,102,108,112,126,130,
%T 138,150,156,162,166,172,180,192,198,210,222,228,232,240,250,256,262,
%U 270,276,282,292,306,312,316,330,336,348,352,358,366,372,378,382,388
%N a(n) = phi(A067774(n)) where phi is Euler totient function.
%C Count of numbers smaller than and coprime to p for primes p such that p + 2 is composite.
%C Subsequence of A006093.
%H Vincenzo Librandi, <a href="/A141515/b141515.txt">Table of n, a(n) for n = 1..6970</a>
%t EulerPhi[#]&@Select[Prime@Range@80, !PrimeQ[# + 2] &] (* _Vincenzo Librandi_, Feb 09 2018 *)
%o (PARI) {forprime(p=2, 400, if(!isprime(p+2), print1(eulerphi(p), ",")))} \\ _Klaus Brockhaus_, Aug 31 2008
%o (Magma) [EulerPhi(p): p in PrimesUpTo(400) | not IsPrime(p+2)]; // _Vincenzo Librandi_, Feb 09 2018
%Y Cf A067774 (primes p such that p+2 is composite), A000010 (Euler totient function), A006093 (primes minus 1), A141426, A141427.
%K nonn
%O 1,2
%A _Giovanni Teofilatto_, Aug 11 2008
%E Edited and a(1) = 1, a(12) = 66 inserted by _Klaus Brockhaus_, Aug 31 2008
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