func fibNumber() func() int {
fib1, fib2 := 0, 1
return func() int {
fib1, fib2 = fib2, fib1 + fib2
return fib1
}
func fibSequence(n int) int {
f := fibNumber()
fib := 0
for i := 0; i < n; i++ {
fib = f()
return fib