This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A243290 #15 Mar 04 2024 01:36:13
%S A243290 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 A243290 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 A243290 11,15,8,25,26,7,27,4,16,28,29,5,12
%N A243290 The index of the greatest prime dividing the n-th squarefree number: a(n) = A061395(A005117(n)).
%H A243290 Antti Karttunen, <a href="/A243290/b243290.txt">Table of n, a(n) for n = 1..10000</a>
%F A243290 a(n) = A061395(A005117(n)) = A049084(A006530(A005117(n))).
%F A243290 For all n>1, a(n) = A070939(A048672(n)).
%t A243290 Table[PrimePi[FactorInteger[k][[-1, 1]]], {k, Select[Range[120], SquareFreeQ]}] (* _Amiram Eldar_, Mar 04 2024 *)
%Y A243290 Cf. A005117, A006530, A061395, A049084, A048672, A070939, A243289.
%K A243290 nonn
%O A243290 1,3
%A A243290 _Antti Karttunen_, Jun 03 2014