Double sum
Hello,
I would like SAGE to compute a double sum like ∑1≤a≤n∑1≤b≤nmax. The result is strange :
f(n)=sum(sum(max(a,b),b,1,n),a,1,n)
SAGE tells me that f(2) is 6. But it is rather 7 (unless i am very tired).
Thank you for your advices :-)
Pierre