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A070929 Smallest integer >= 0 of the form x^2 - n^3. 6
0, 0, 1, 9, 0, 19, 9, 18, 17, 0, 24, 38, 36, 12, 65, 106, 0, 128, 97, 30, 100, 148, 168, 154, 100, 0, 113, 198, 249, 260, 225, 138, 356, 163, 297, 389, 0, 423, 353, 217, 9, 248, 441, 17, 80, 79, 8, 506, 297, 0, 316, 574, 17, 119, 145, 89, 784, 568, 252, 737, 225, 548 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

COMMENTS

a(n)=0 iff n is a square.

LINKS

Table of n, a(n) for n=0..61.

FORMULA

a(n) = ceiling(n^(3/2))^2 - n^3 = A077115(n) - n^3.

EXAMPLE

A077115(10) = 1024 = 32^2 is the least square >= 10^3 = 1000, therefore a(10) = 1024 - 1000 = 24.

MATHEMATICA

f[n_]=Ceiling[n^(3/2)]^2-n^3;

t1=Table[f[n], {n, 1, 90}]; t1 (* Clark Kimberling, Jan 30 2011 *)

PROG

(PARI) for(n=1, 100, print1(ceil(n^(3/2))^2-n^3, ", "))

CROSSREFS

Cf. A000578, A077116, A077118, A077119, A077109, A068527.

Sequence in context: A117465 A136679 A299154 * A007394 A067153 A057405

Adjacent sequences:  A070926 A070927 A070928 * A070930 A070931 A070932

KEYWORD

easy,nonn

AUTHOR

Benoit Cloitre, May 20 2002

STATUS

approved

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Last modified July 21 19:25 EDT 2019. Contains 325199 sequences. (Running on oeis4.)