Floyd's triangle   lists the natural numbers in a right triangle aligned to the left where

 the first row is   1     (unity)
 successive rows start towards the left with the next number followed by successive naturals listing one more number than the line above.


The first few lines of a Floyd triangle looks like this:

 1
 2  3
 4  5  6
 7  8  9 10
11 12 13 14 15



Task

 Write a program to generate and display here the first   n   lines of a Floyd triangle. 
(Use   n=5   and   n=14   rows).
 Ensure that when displayed in a mono-space font, the numbers line up in vertical columns as shown and that only one space separates numbers of the last row.


package main
 
import "fmt"
 
func main() {
    floyd(5)
    floyd(14)
}
 
func floyd(n int) {
    fmt.Printf("Floyd %d:\n", n)
    lowerLeftCorner := n*(n-1)/2 + 1
    lastInColumn := lowerLeftCorner
    lastInRow := 1
    for i, row := 1, 1; row <= n; i++ {
        w := len(fmt.Sprint(lastInColumn))
        if i < lastInRow {
            fmt.Printf("%*d ", w, i)
            lastInColumn++
        } else {
            fmt.Printf("%*d\n", w, i)
            row++
            lastInRow += row
            lastInColumn = lowerLeftCorner
        }
    }
}