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A365786 a(n) = squarefree kernel of A286708(n). 5

%I #10 Sep 20 2023 12:21:08

%S 6,6,10,6,6,14,10,6,15,6,6,14,10,6,21,22,10,6,6,15,26,14,10,6,30,22,6,

%T 10,33,15,6,34,35,6,21,26,14,38,39,14,10,6,42,30,22,6,10,15,46,6,34,

%U 10,6,51,30,26,14,38,6,55,21,14,10,57,33,58,15,6,42,30,62

%N a(n) = squarefree kernel of A286708(n).

%C Terms are squarefree and composite, i.e., in A120944.

%H Michael De Vlieger, <a href="/A365786/b365786.txt">Table of n, a(n) for n = 1..10000</a>

%F a(n) = A007947(A286708(n)).

%e Let b(n) = A286708(n) and let squarefree kernel rad(n) = A007947(n).

%e a(1) = 6 = rad(b(1)) = rad(36).

%e a(2) = 6 = rad(b(2)) = rad(72).

%e a(3) = 10 = rad(b(3)) = rad(100), etc.

%t With[{nn = 2^12}, Map[Times @@ FactorInteger[#][[All, 1]] &, Rest@ Select[Union@ Flatten@ Table[a^2*b^3, {b, nn^(1/3)}, {a, Sqrt[nn/b^3]}], Not @* PrimePowerQ]] ]

%o (PARI) apply(x->factorback(factorint(x)[, 1]), select(x->((x>1) && ispowerful(x) && !isprimepower(x)), [1..5000])) \\ _Michel Marcus_, Sep 20 2023

%Y Cf. A001694, A007947, A084371, A120944, A126706, A286708.

%K nonn

%O 1,1

%A _Michael De Vlieger_, Sep 19 2023

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Last modified August 24 02:14 EDT 2024. Contains 375396 sequences. (Running on oeis4.)