Answer :
I'm writing that in some sort of pseudocode; if you don't understand it, feel free to ask for more details in the comments.
function sumOdd(n)
if n==1 then
return 1
end if
return (sumOdd(n-1))+(n*2-1)
end function
function sumOdd(n)
if n==1 then
return 1
end if
return (sumOdd(n-1))+(n*2-1)
end function
