OFFSET
0,2
COMMENTS
a(n) is number of nonnegative integer solutions (x,x,z,u) such that x + y^2 + z^3 + u^4 = n.
FORMULA
G.f.: (Sum_{i>=0} x^(i^2)) * (Sum_{j>=0} x^(j^3)) * (Sum_{k>=0} x^(k^4)) / (1-x).
CROSSREFS
KEYWORD
nonn
AUTHOR
Ran Pan, Oct 03 2015
STATUS
approved