# How to Compute a Cube as Sums in Golang

## The challenge

You will be given a number `n` (where `n >= 1`) and your task is to find `n` consecutive odd numbers whose sum is exactly the cube of `n`.

**Mathematically:
** cube = n ** 3
sum = a1 + a2 + a3 + ….. + an
sum == cube
a2 == a1 + 2, a3 == a2 + 2, …….

For example:

``````FindSummands(3) == []int{7,9,11}
// ..because 7 + 9 + 11 = 27, the cube of 3.
// Note that there are only n = 3 elements in the array.
``````

Write function `findSummands(n)` which will return an array of n consecutive odd numbers with the sum equal to the cube of n `(n*n*n)`.

## The solution in Golang

Option 1:

``````package solution
func FindSummands(n int) []int {
res := []int{}
y := n * n - n + 1
for i := 0; i<n; i++ {
res = append(res, y + 2 * i)
}
return res
}
``````

Option 2:

``````package solution
func FindSummands(n int) []int {
a := n*n - n + 1
res := make([]int, n)
for i := 0; i < n; i++ {
res[i] = a + i*2
}
return res
}
``````

Option 3:

``````package solution
func FindSummands(n int) []int {
a:=n*n-n+1; arr:=make([]int, n)
for i:=0; i<n; i++ { arr[i] = a; a+=2 }
return arr
}
``````

## Test cases to validate our solution

``````package solution_test

import (
"fmt"
. "github.com/onsi/ginkgo"
. "github.com/onsi/gomega"
)

var _ = Describe("Example Tests: 1 through 4",func() {
test_sols := [...][]int{
[]int{1},
[]int{3,5},
[]int{7,9,11},
[]int{13,15,17,19},
}
for i,v := range []int{1,2,3,4} {
It(fmt.Sprintf("test for number %d",v),func() {
num := FindSummands(v)
Expect(num).To(Equal(test_sols[i]))})
}
})
``````