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A064804 Numbers k such that phi(2*k + 2) < phi(2*k). 1

%I

%S 16,22,28,34,38,40,46,52,58,64,68,76,82,86,88,94,98,100,106,112,118,

%T 124,128,130,134,136,142,148,152,154,158,160,166,172,178,184,188,190,

%U 194,196,202,206,208,214,218,220,226,232,236,238,244,248,250,256,262,268

%N Numbers k such that phi(2*k + 2) < phi(2*k).

%H Harry J. Smith, <a href="/A064804/b064804.txt">Table of n, a(n) for n = 1..1000</a>

%t 2Select[ Range[200], EulerPhi[2# + 2] < EulerPhi[2# ] & ]

%o (PARI) { n=e=0; forstep (m=2, 10^9, 2, f=eulerphi(m); if (f<e, write("b064804.txt", n++, " ", m - 2); if (n==1000, return)); e=f ) } \\ _Harry J. Smith_, Sep 26 2009

%Y Cf. A001837.

%K easy,nonn

%O 1,1

%A _Robert G. Wilson v_, Oct 21 2001

%E a(41)-a(56) from _Harry J. Smith_, Sep 26 2009

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Last modified November 18 04:44 EST 2019. Contains 329248 sequences. (Running on oeis4.)