OFFSET
0,2
COMMENTS
LINKS
Colin Barker, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (5,-10,10,-5,1).
FORMULA
a(n) = floor(Sum_{j=n^3+1..(n+1)^3-1} j^(2/3)).
a(n) = 2*n + 5*n^2 + 6*n^3 + 3*n^4.
G.f.: -8*x*(x+2)*(2*x+1) / (x-1)^5. - Colin Barker, Dec 30 2014
E.g.f.: exp(x)*x*(16 + 44*x + 24*x^2 + 3*x^3). - Stefano Spezia, Jul 13 2024
MATHEMATICA
Table[2 n + 5 n^2 + 6 n^3 + 3 n^4, {n, 0, 50}]
PROG
(PARI) a(n) = floor(sum(j=n^3+1, (n+1)^3-1, j^(2/3))); \\ Michel Marcus, Dec 22 2014
(PARI) concat(0, Vec(-8*x*(x+2)*(2*x+1)/(x-1)^5 + O(x^100))) \\ Colin Barker, Dec 30 2014
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Richard R. Forberg, Dec 02 2014
STATUS
approved