program perm
	local n=`1'
	local r=1
	forv i=1/`n' {
		local r=`r'*`i'
	}
	clear
	qui set obs `r'
	forv i=1/`n' {
		gen p`i'=0
	}
	mata: genperm()
end

mata
void genperm() {
	real scalar n, i, j, k, s, p
	real rowvector u
	st_view(a=., ., .)
	n = cols(a)
	u = 1..n
	p = 1
	do {
		a[p++, .] = u
		for (i = n; i > 1; i--) {
			if (u[i-1] < u[i]) break
		}
		if (i > 1) {
			j = i
			k = n
			while (j < k) u[(j++, k--)] = u[(k, j)]
			
			s = u[i-1]
			for (j = i; u[j] < s; j++) {
			}
			u[i-1] = u[j]
			u[j] = s
		}
	} while (i > 1)
}
end