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A175030 a(n)=3*n if n is prime, otherwise a(n)=2*n. 0

%I #2 Mar 30 2012 17:26:31

%S 2,6,9,8,15,12,21,16,18,20,33,24,39,28,30,32,51,36,57,40,42,44,69,48,

%T 50,52,54,56,87,60,93,64,66,68,70,72,111,76,78,80,123,84,129,88,90,92,

%U 141,96,98,100,102,104,159,108,110,112,114,116,177,120,183,124,126,128,130

%N a(n)=3*n if n is prime, otherwise a(n)=2*n.

%t Table[If[PrimeQ[n],3*n,2*n],{n,1,200}]

%Y Cf. A068519, A167480, A167482, A175027, A175028, A175029.

%K nonn

%O 1,1

%A _Zak Seidov_, Nov 04 2009

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Last modified June 19 18:58 EDT 2024. Contains 373507 sequences. (Running on oeis4.)