A025465 - OEIS

A025465

Number of partitions of n into 3 distinct nonnegative cubes.

0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0

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OFFSET

0,856

COMMENTS

In other words, number of solutions to the equation n = x^3 + y^3 + z^3 with x > y > z >= 0. - Antti Karttunen, Aug 29 2017

LINKS

Antti Karttunen, Table of n, a(n) for n = 0..17073

Index entries for sequences related to sums of cubes

FORMULA

a(n) = A025468(n) + A025469(n).

EXAMPLE

From Antti Karttunen, Aug 29 2017: (Start)

For n = 9 there is one solution: 9 = 2^3 + 1^3 + 0^3, thus a(9) = 1.

For n = 855 there are two solutions: 855 = 9^3 + 5^3 + 1^3 = 8^3 + 7^3 + 0^3, thus a(855) = 2. This is also the first point where sequence attains value greater than one.

(End)

From Harvey P. Dale, Sep 30 2018: (Start)

In addition to 855, the following numbers attain the value of 2: 1009, 1072, 1366, 1457, and there are 73 more such numbers less than 10000.

The first two numbers to attain the value of 3 are 5104 and 9729.

There are no numbers up to 10000 that attain a value greater than 3.

(End)

MATHEMATICA

Table[Length[FindInstance[{n==x^3+y^3+z^3, x>y>z>=0}, {x, y, z}, Integers, 5]], {n, 0, 110}] (* Harvey P. Dale, Sep 30 2018 *)

PROG

(PARI) A025465(n) = { my(s=0); for(x=0, n, if(ispower(x, 3), for(y=x+1, n-x, if(ispower(y, 3), for(z=y+1, n-(x+y), if((ispower(z, 3)&&(x+y+z)==n), s++)))))); (s); }; \\ Antti Karttunen, Aug 29 2017

CROSSREFS

Cf. A025468, A025469, A001239.

Sequence in context: A239705 A025468 A373971 * A323514 A369660 A353495

Adjacent sequences: A025462 A025463 A025464 * A025466 A025467 A025468

KEYWORD

nonn

AUTHOR

David W. Wilson

STATUS

approved