A340979 Number of ways to write n as an ordered sum of 6 positive cubes.

1, 0, 0, 0, 0, 0, 0, 6, 0, 0, 0, 0, 0, 0, 15, 0, 0, 0, 0, 0, 0, 20, 0, 0, 0, 0, 6, 0, 15, 0, 0, 0, 0, 30, 0, 6, 0, 0, 0, 0, 60, 0, 1, 0, 0, 0, 0, 60, 0, 0, 0, 0, 15, 0, 30, 0, 0, 0, 0, 60, 0, 6, 0, 6, 0, 0, 90, 0, 0, 0, 30, 0, 0, 60, 0, 0, 0, 60, 20, 0, 15, 0, 0, 0, 60, 60, 0, 0, 0, 30, 0, 30, 60

Offset

6,8

Links

Robert Israel, Table of n, a(n) for n = 6..10000

Index entries for sequences related to sums of cubes

Formula

G.f.: (Sum_{k>=1} x^(k^3))^6.

Maple

b:= proc(n, t) option remember;
      `if`(n=0, `if`(t=0, 1, 0), `if`(t<1, 0, add((s->
      `if`(s>n, 0, b(n-s, t-1)))(j^3), j=1..iroot(n, 3))))
    end:
a:= n-> b(n, 6):
seq(a(n), n=6..98);  # Alois P. Heinz, Feb 01 2021

Mathematica

nmax = 98; CoefficientList[Series[Sum[x^(k^3), {k, 1, Floor[nmax^(1/3)] + 1}]^6, {x, 0, nmax}], x] // Drop[#, 6] &

Crossrefs

Cf. A000578, A010057, A025459, A051344, A173680, A280618, A340977, A340978, A340980, A340981, A340982, A340983.

Sequence in context: A331428 A323487 A173453 * A102638 A187794 A200214

Adjacent sequences: A340976 A340977 A340978 * A340980 A340981 A340982

Keyword

nonn

Author

Ilya Gutkovskiy, Feb 01 2021

Status

approved