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Smallest nontrivial extension of n-th cube which is a cube not ending 000.
2

%I #8 May 24 2016 23:53:30

%S 125,85184,2744,6434856,1259712,2161700757,34328125,5124031424,

%T 7290099019,10007873875,13312053,172808693,21975528401,274498269499,

%U 337589698347,409675763483,491355848971,58320792152,68593724400375

%N Smallest nontrivial extension of n-th cube which is a cube not ending 000.

%H Chai Wah Wu, <a href="/A030697/b030697.txt">Table of n, a(n) for n = 1..10000</a>

%o (Python)

%o from gmpy2 import iroot

%o def A030697(n):

%o d, nd = 10, 10*n**3

%o while True:

%o x = iroot(nd-1,3)[0]+1

%o if not x % 10:

%o x += 1

%o x = x**3

%o if x < nd+d:

%o return int(x)

%o d *= 10

%o nd *= 10 # _Chai Wah Wu_, May 24 2016

%Y Cf. A030698.

%K nonn,base

%O 1,1

%A _Patrick De Geest_