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A030668 Smallest nontrivial extension of n which is a cube.

%I A030668 #8 May 24 2016 23:52:31
%S A030668 125,27,343,4096,512,64,729,8000,9261,1000,110592,125,1331,140608,
%T A030668 15625,166375,1728,185193,19683,205379,216,226981,238328,24389,250047,
%U A030668 262144,2744,287496,29791,300763,314432,32768,3375,343,35937
%N A030668 Smallest nontrivial extension of n which is a cube.
%H A030668 Chai Wah Wu, <a href="/A030668/b030668.txt">Table of n, a(n) for n = 1..10000</a>
%o A030668 (Python)
%o A030668 from gmpy2 import iroot
%o A030668 def A030668(n):
%o A030668     d, nd = 10, 10*n
%o A030668     while True:
%o A030668         x = (iroot(nd-1,3)[0]+1)**3
%o A030668         if x < nd+d:
%o A030668             return int(x)
%o A030668         d *= 10
%o A030668         nd *= 10 # _Chai Wah Wu_, May 24 2016
%Y A030668 Cf. A030669.
%K A030668 nonn,base
%O A030668 1,1
%A A030668 _Patrick De Geest_