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%I A128972 #12 May 05 2017 10:56:38
%S A128972 7,26,63,124,215,342,511,91,37,1330,1727,2196,2743,3374,4095,614,17,
%T A128972 254,7999,9260,10647,12166,13823,1953,17575,19682,813,24388,26999,
%U A128972 29790,32767,4492,39303,42874,46655,1876,54871,59318,63999,8615,74087,79506
%N A128972 n^3 - 1 divided by its largest cube divisor.
%C A128972 In other words, cubefree part of n^3-1, or cubefree kernel of n^3-1. Cube analog of A068310.
%H A128972 Robert Israel, <a href="/A128972/b128972.txt">Table of n, a(n) for n = 2..10000</a>
%F A128972 a(n) = A062378(A068601(n)) = A062378(n^3-1).
%e A128972 a(9) = (9^3-1)/8 = (2^3 * 7 * 13)/(2^3) = 728/8 = 91.
%e A128972 a(10) = (10^3-1)/27 = (3^3 * 37)/(3^3) = 999/27 = 37.
%e A128972 a(18) = (18^3-1)/343 = (7^3 * 17)/(7^3) = 5831/343 = 17.
%p A128972 a:= n -> mul(f[1]^(f[2] mod 3), f = ifactors(n^3-1)[2]):
%p A128972 seq(a(n),n=2..100); # _Robert Israel_, Sep 24 2014
%Y A128972 Cf. A002350, A004709, A007948, A062378, A067872, A033314, A068310.
%K A128972 easy,nonn
%O A128972 2,1
%A A128972 _Jonathan Vos Post_, Apr 28 2007
%E A128972 More terms from _Carl R. White_, Nov 09 2010

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