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Smallest integer >= 0 of the form x^4 - n^3.
0

%I #10 Jan 03 2021 12:32:23

%S 0,8,54,17,131,40,282,113,567,296,1070,673,204,1352,721,0,1648,729,

%T 3141,2000,739,3993,2474,817,5111,3160,1053,6609,4172,1561,8625,5648,

%U 2479,11321,7750,3969,14883,10664,6217,1536,14600,9433,4014,19792

%N Smallest integer >= 0 of the form x^4 - n^3.

%C a(n)=0 if n is a power of 4.

%F a(n) = ceiling(n^(3/4))^4 - n^3.

%t si[n_]:=Module[{k=Ceiling[Surd[n^3,4]]},While[!Integer[k^4-n^3],k++];k^4-n^3]; Array[si,50] (* _Harvey P. Dale_, Jan 03 2021 *)

%o (PARI) for(n=1,100,print1(ceil(n^(3/4))^4-n^3,","))

%Y Cf. A068527.

%K easy,nonn

%O 1,2

%A _Benoit Cloitre_, May 20 2002