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A072751 Greatest of the most frequent prime factors of squarefree numbers <= n; a(1)=1. 4

%I

%S 1,2,3,5,3,3,2,2,2,2,2,2,2,3,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,

%T 2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,

%U 2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2

%N Greatest of the most frequent prime factors of squarefree numbers <= n; a(1)=1.

%C a(n)=2 for n>14.

%t max = 200; primeFactors = FactorInteger[#][[All, 1]]& /@ Select[Range[max], SquareFreeQ]; a[n_] := Sort[ Tally[ Take[ primeFactors, n] // Flatten], Which[#1[[2]] > #2[[2]], True, #1[[2]] == #2[[2]], #1[[1]] > #2[[1]], True, False]& ][[1, 1]]; Table[a[n], {n, 1, primeFactors // Length}] (* _Jean-Fran├žois Alcover_, Oct 14 2013 *)

%Y Cf. A005117, A072747, A072748, A072749, A072750.

%K nonn,nice

%O 1,2

%A _Reinhard Zumkeller_, Jul 08 2002

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Last modified April 7 04:20 EDT 2020. Contains 333292 sequences. (Running on oeis4.)