OFFSET
0,1
COMMENTS
a(n)= sum(j3^2*sum(j2^2*sum(j1^2,j1=1..j2+1),j2=1..j3+1),j3=1..n), threefold iterated sums of squares).
LINKS
Indranil Ghosh, Table of n, a(n) for n = 0..5000
FORMULA
MATHEMATICA
Table[Binomial[n+6, 6]*(280*n^3+2436*n^2+5906n+3843)/63, {n, 0, 19}] (* Indranil Ghosh, Feb 21 2017 *)
PROG
(Python)
import math
def C(n, r):
....f=math.factorial
....return f(n)/f(r)/f(n-r)
def A060061(n):
....return (C(n+6, 6)*(280*n**3+2436*n**2+5906*n+3843))/63 # Indranil Ghosh, Feb 21 2017
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Wolfdieter Lang, Mar 16 2001
STATUS
approved