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%I #16 Oct 14 2018 08:02:19
%S 1,1,1,4,4,6,6,8,9,10,10,12,12,14,15,16,16,18,18,20,21,22,22,24,25,26,
%T 27,28,28,30,30,32,33,34,35,36,36,38,39,40,40,42,42,44,45,46,46,48,49,
%U 50,51,52,52,54,55,56,57,58,58,60,60,62,63,64,65,66,66,68,69,70,70,72
%N Largest nonprime integer not less than n.
%F For n > 3: a(n) = A113523(n) = A014684(n);
%F For n > 0: a(n) = A113638(n). - _Georg Fischer_, Oct 12 2018
%F A005171(a(n)) = 1; A010051(a(n)) = 0.
%t Array[# - Boole[PrimeQ@ #] - Boole[# == 3] &, 72] (* _Michael De Vlieger_, Oct 13 2018 *)
%o (PARI) a(n) = if (isprime(n), if (n==3, 1, n-1), n); \\ _Michel Marcus_, Oct 13 2018
%Y Cf. A007917, A014684, A018252, A113523, A113638.
%K nonn,easy
%O 1,4
%A _Reinhard Zumkeller_, Jul 08 2010
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