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Difference between smallest cube > n and n.
1

%I #10 Apr 05 2021 18:46:25

%S 1,7,6,5,4,3,2,1,19,18,17,16,15,14,13,12,11,10,9,8,7,6,5,4,3,2,1,37,

%T 36,35,34,33,32,31,30,29,28,27,26,25,24,23,22,21,20,19,18,17,16,15,14,

%U 13,12,11,10,9,8,7,6,5,4,3,2,1,61,60,59,58,57,56,55,54,53,52,51,50,49,48,47,46,45

%N Difference between smallest cube > n and n.

%C a(n) is the smallest positive number k such that n + k is a cube.

%H Michael De Vlieger, <a href="/A333884/b333884.txt">Table of n, a(n) for n = 0..9999</a>

%F a(n) = floor(n^(1/3) + 1)^3 - n.

%t Table[Floor[n^(1/3) + 1]^3 - n, {n, 0, 80}]

%Y Cf. A000578, A048763, A055400, A068527, A080883, A154840.

%K nonn

%O 0,2

%A _Ilya Gutkovskiy_, Apr 08 2020