A262872 - OEIS

A262872

Expansion of (Sum_{i>=0} x^(i^2)) * (Sum_{j>=0} x^(j^3)) / (1-x).

1, 3, 4, 4, 5, 6, 6, 6, 7, 9, 10, 10, 11, 11, 11, 11, 12, 14, 14, 14, 14, 14, 14, 14, 15, 16, 17, 18, 19, 19, 19, 20, 20, 21, 21, 21, 23, 24, 24, 24, 24, 24, 24, 25, 26, 26, 26, 26, 26, 27, 28, 28, 29, 29, 29, 29, 29, 30, 30, 30, 30, 30, 30, 31, 32, 33, 33, 33, 34, 34, 34

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OFFSET

0,2

COMMENTS

a(n) is number of nonnegative integer solutions (x,y,z) such that x + y^2 + z^3 = n.

LINKS

Table of n, a(n) for n=0..70.

FORMULA

G.f.: (Sum_{i>=0} x^(i^2)) * (Sum_{j>=0} x^(j^3)) / (1-x).

EXAMPLE

a(4) = 5 because there are 5 solutions: (5,0,0), (4,1,0), (4,0,1), (3,1,1) and (1,2,0).

CROSSREFS