A070928 Smallest integer >= 0 of the form x^4 - n^3.

0, 8, 54, 17, 131, 40, 282, 113, 567, 296, 1070, 673, 204, 1352, 721, 0, 1648, 729, 3141, 2000, 739, 3993, 2474, 817, 5111, 3160, 1053, 6609, 4172, 1561, 8625, 5648, 2479, 11321, 7750, 3969, 14883, 10664, 6217, 1536, 14600, 9433, 4014, 19792

Offset

1,2

Comments

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

Links

Table of n, a(n) for n=1..44.

Formula

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

Mathematica

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 *)

Prog

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

Crossrefs

Cf. A068527.

Sequence in context: A293115 A337554 A370359 * A180095 A234955 A189393

Adjacent sequences: A070925 A070926 A070927 * A070929 A070930 A070931

Keyword

easy,nonn

Author

Benoit Cloitre, May 20 2002

Status

approved