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A243290 The index of the greatest prime dividing the n-th squarefree number: a(n) = A061395(A005117(n)). 4

%I #15 Mar 04 2024 01:36:13

%S 0,1,2,3,2,4,3,5,6,4,3,7,8,4,5,9,6,10,3,11,5,7,4,12,8,6,13,4,14,9,15,

%T 7,16,5,8,10,17,18,11,6,5,19,9,4,20,21,12,5,6,22,13,23,7,14,10,24,6,

%U 11,15,8,25,26,7,27,4,16,28,29,5,12

%N The index of the greatest prime dividing the n-th squarefree number: a(n) = A061395(A005117(n)).

%H Antti Karttunen, <a href="/A243290/b243290.txt">Table of n, a(n) for n = 1..10000</a>

%F a(n) = A061395(A005117(n)) = A049084(A006530(A005117(n))).

%F For all n>1, a(n) = A070939(A048672(n)).

%t Table[PrimePi[FactorInteger[k][[-1, 1]]], {k, Select[Range[120], SquareFreeQ]}] (* _Amiram Eldar_, Mar 04 2024 *)

%Y Cf. A005117, A006530, A061395, A049084, A048672, A070939, A243289.

%K nonn

%O 1,3

%A _Antti Karttunen_, Jun 03 2014

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Last modified May 5 00:40 EDT 2024. Contains 372257 sequences. (Running on oeis4.)