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%I #13 Jun 18 2022 19:10:56
%S 13,16,19,22,23,25,28,31,34,37,38,40,43,46,47,49,52,53,55,58,61,64,67,
%T 68,73,76,79,82,83,85,86,88,89,91,94,97,98,100,103,106,109,112,113,
%U 115,118,121,124,127,128,130,131,133,134,136,139,142,143,145,148,151,152
%N Numbers k such that phi(k) > phi(k+2).
%H Harry J. Smith, <a href="/A064805/b064805.txt">Table of n, a(n) for n = 1..1000</a>
%t Select[ Range[150], EulerPhi[ # ] > EulerPhi[ #+2 ] & ]
%t Position[Partition[EulerPhi[Range[200]],3,1],_?(First[#]>Last[#]&), 1, Heads->False]//Flatten (* _Harvey P. Dale_, Jun 14 2017 *)
%o (PARI) { n=0; for (m=1, 10^9, f=eulerphi(m); if (eulerphi(m)>eulerphi(m + 2), write("b064805.txt", n++, " ", m); if (n==1000, return)) ) } \\ _Harry J. Smith_, Sep 26 2009
%Y Cf. A000010 (phi), A001837.
%K easy,nonn
%O 1,1
%A _Robert G. Wilson v_, Oct 21 2001
%E a(60)-a(61) from _Harry J. Smith_, Sep 26 2009
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