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 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