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A272605 a(1) = 1, for n>=1 a(n) is the largest prime factor of A002182(n).

%I A272605 #7 Nov 01 2016 10:10:16
%S A272605 1,2,2,3,3,3,3,3,5,5,5,5,5,5,7,7,7,7,7,7,7,7,7,7,11,7,7,11,11,11,11,
%T A272605 11,11,11,11,11,11,13,13,13,13,13,13,13,13,13,13,13,13,13,13,13,17,13,
%U A272605 17,17,17,17,17,17,17,17,17,17,19,17,17,19,19,17,19,19,19,19,19,19,19,19,19,19,19,19,23,19,23,19
%N A272605 a(1) = 1, for n>=1 a(n) is the largest prime factor of A002182(n).
%C A272605 For n>=1, the largest prime factor of the n-th highly composite number.
%H A272605 Joerg Arndt, <a href="/A272605/b272605.txt">Table of n, a(n) for n = 1..19999</a>
%e A272605 The first highly composite numbers with their prime factorizations:
%e A272605 n:  A002182(n) = [factorization]
%e A272605 1:  1  = []
%e A272605 2:  2   = [2]
%e A272605 3:  4   = [2^2]
%e A272605 4:  6   = [2 * 3]
%e A272605 5:  12   = [2^2 * 3]
%e A272605 6:  24   = [2^3 * 3]
%e A272605 7:  36   = [2^2 * 3^2]
%e A272605 8:  48   = [2^4 * 3]
%e A272605 9:  60   = [2^2 * 3 * 5]
%e A272605 10:  120   = [2^3 * 3 * 5]
%e A272605 11:  180   = [2^2 * 3^2 * 5]
%e A272605 12:  240   = [2^4 * 3 * 5]
%e A272605 13:  360   = [2^3 * 3^2 * 5]
%e A272605 14:  720   = [2^4 * 3^2 * 5]
%e A272605 15:  840   = [2^3 * 3 * 5 * 7]
%e A272605 16:  1260   = [2^2 * 3^2 * 5 * 7]
%e A272605 17:  1680   = [2^4 * 3 * 5 * 7]
%e A272605 18:  2520   = [2^3 * 3^2 * 5 * 7]
%e A272605 19:  5040   = [2^4 * 3^2 * 5 * 7]
%e A272605 20:  7560   = [2^3 * 3^3 * 5 * 7]
%e A272605 21:  10080   = [2^5 * 3^2 * 5 * 7]
%e A272605 22:  15120   = [2^4 * 3^3 * 5 * 7]
%e A272605 23:  20160   = [2^6 * 3^2 * 5 * 7]
%e A272605 24:  25200   = [2^4 * 3^2 * 5^2 * 7]
%e A272605 25:  27720   = [2^3 * 3^2 * 5 * 7 * 11]
%e A272605 26:  45360   = [2^4 * 3^4 * 5 * 7]
%e A272605 27:  50400   = [2^5 * 3^2 * 5^2 * 7]
%e A272605 28:  55440   = [2^4 * 3^2 * 5 * 7 * 11]
%e A272605 29:  83160   = [2^3 * 3^3 * 5 * 7 * 11]
%e A272605 30:  110880   = [2^5 * 3^2 * 5 * 7 * 11]
%K A272605 nonn
%O A272605 1,2
%A A272605 _Joerg Arndt_, Nov 01 2016