A135682 - OEIS

%I #7 Oct 26 2016 11:33:34

%S 1,2,3,4,5,4,7,4,7,4,11,4,13,4,7,4,17,4,19,4,7,4,23,4,7,4,7,4,29,4,31,

%T 4,7,4,7,4,37,4,7,4,41,4,43,4,7,4,47,4,7,4,7,4,53,4,7,4,7,4,59,4,61,4,

%U 7,4,7,4,67,4,7,4,71,4,73

%N a(n)=n if n=1 or if n=prime. Otherwise, n=4 if n is even and n=7 if n is odd.

%H G. C. Greubel, <a href="/A135682/b135682.txt">Table of n, a(n) for n = 1..1000</a>

%t a[n_] := If[PrimeQ[n] || n == 1, n, If[EvenQ[n], 4, 7] ]; Table[a[n], {n,1,25}] (* _G. C. Greubel_, Oct 26 2016 *)

%Y Cf. A000027; A000040; A135679; A135680; A014681; A014682; A014683; A014684; A014685; A014686; A014687; A014688; A014689; A014690; A135681.

%K nonn

%O 1,2

%A _Mohammad K. Azarian_, Dec 01 2007