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A069549 Smallest composite k such that phi(k) > k*(1-1/n). 2

%I

%S 4,4,9,25,25,49,49,121,121,121,121,169,169,289,289,289,289,361,361,

%T 529,529,529,529,841,841,841,841,841,841,961,961,1369,1369,1369,1369,

%U 1369,1369,1681,1681,1681,1681,1849,1849,2209,2209,2209,2209,2809,2809,2809

%N Smallest composite k such that phi(k) > k*(1-1/n).

%C Or, least composite k such that k is coprime to the n-1 numbers k+1 ... k+n-1. E.g. a(4) = 25 because 25 is coprime to 26, 27 and 28. - _Amarnath Murthy_, Apr 20 2004

%F a(n)=nextprime(n)^2=A007918(n)^2

%Y Cf. A052349.

%K easy,nonn

%O 1,1

%A _Benoit Cloitre_, Apr 21 2002

%E Edited by _David Wasserman_, Apr 23 2007

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Last modified January 19 20:26 EST 2019. Contains 319310 sequences. (Running on oeis4.)