/*
 * Il seguente programma stampa h numeri n-poligonali
 *
 * (Ref. http://mathworld.wolfram.com/PolygonalNumber.html) 
 * (Ref. http://blogaritmico.planetweblog.net/weblog/blogs/index.php/2006/08/27/numeri_poligonali)
 *
 */

#include <stdio.h>

unsigned int polynum(unsigned int, unsigned int);

int
main(void)
{
	unsigned int side = 2, numbers, i;

	/* read polygonal side, how much numbers to print */
	while (side < 3) {
		printf("Enter the polygonal number ( > 2): ");
		scanf("%u", &side);

		if (side < 3)
			printf("Invalid value!\n");
	}

	printf("How much numbers? ");
	scanf("%u", &numbers);

	for (i = 1; i <= numbers; i++)
		printf("%u, ", polynum(side, i));
	if (numbers > 0)
		printf("...\n");

	return 0;
}

unsigned int polynum(unsigned int n, unsigned int h)
{

	if (n < 3)
		return 0;

	return (n - 2) * (h - 1) * h / 2 + h;
}