%I #17 Oct 26 2016 11:42:38
%S 1,2,3,2,5,2,7,2,3,2,11,2,13,2,3,2,17,2,19,2,3,2,23,2,3,2,3,2,29,2,31,
%T 2,3,2,3,2,37,2,3,2,41,2,43,2,3,2,47,2,3,2,3,2,53,2,3,2,3,2,59,2,61,2,
%U 3,2,3,2,67,2,3,2,71,2,73
%N a(n) = n if n = 1 or if n is prime. Otherwise, a(n) = 2 if n is even and a(n) = 3 if n is odd.
%C The average value of a(n) is n/(2 log n) + O(n log log n/log^2 n). - _Charles R Greathouse IV_, May 29 2014
%H G. C. Greubel, <a href="/A135679/b135679.txt">Table of n, a(n) for n = 1..1000</a>
%t a[n_] := If[PrimeQ[n] || n == 1, n, If[EvenQ[n], 2, 3] ]; Table[a[n], {n,1,25}] (* _G. C. Greubel_, Oct 26 2016 *)
%o (PARI) a(n)=if(isprime(n)||n==1, n, if(n%2, 3, 2)) \\ _Charles R Greathouse IV_, May 29 2014
%K nonn,easy
%O 1,2
%A _Mohammad K. Azarian_, Dec 01 2007