A102441 - OEIS

%I #9 Feb 04 2020 03:59:08

%S 1,2,3,4,4,6,6,8,9,8,8,12,8,12,12,16,12,18,12,16,18,16,20,24,16,16,27,

%T 24,20,24,20,32,24,24,24,36,24,24,24,32,30,36,30,32,36,40,44,48,36,32,

%U 36,32,45,54,32,48,36,40,52,48,52,40,54,64,32,48,40,48,60,48,66,72,66

%N a(n) = A102440(A102440(n)).

%C See A102442, A102443 for further iterations of A102440.

%H Amiram Eldar, <a href="/A102441/b102441.txt">Table of n, a(n) for n = 1..10000</a>

%t g[p_] := g[p] = For[k = p - 1, True, k--, If[PrimeOmega[k] == 2, Return[k]]]; f[n_] := Product[{p, e} = pe; If[p <= 3, p, g[p]]^e, {pe, FactorInteger[n]}]; a[n_] := f[f[n]]; Array[a, 100] (* _Amiram Eldar_, Feb 04 2020 after _Jean-François Alcover_ at A102440 *)

%Y Cf. A102440, A102442, A102443.

%K nonn,mult

%O 1,2

%A _Reinhard Zumkeller_, Jan 09 2005