find largest 32-bit Pythagorean integer triple with a 64-bit square

pythag.c

#include <stdio.h>

/*
 * cc -O2 pythag.c -o pythag
 *
 * find largest 32-bit Pythagorean integer triple with a 64-bit square
 */

typedef unsigned long long ulong;

const ulong l = 65536;

ulong main(ulong argc, char **argv)
{
	ulong lm, ln, a, b, c, la, lb, lc = 0;

	for (ulong n = 1; n < l; n++)
	{
		for (ulong m = n+1; m < l; m++)
		{
			// Euclid's formula for Pythagorean triples
			a   =        m*m-n*n;
			b   =        2*m*n;
			c   =        m*m+n*n;
			// where a^2 + b^2 = c^2

			// save largest observed 32-bit c value
			if (c < (1ull<<32) && c > lc) {
				lm = m, ln = n, la = a, lb = b, lc = c;
			}
		}
	}

	printf("m=#%llx n=#%llx a=#%llx b=#%llx c=#%llx c^2=#%llx\n",
		lm, ln, la, lb, lc, lc*lc);
}

pythag.md

./pythag
m=#f9ee n=#376b a=#e801b28b b=#6c3530f4 c=#fffffffd c^2=#fffffffa00000009