Răspuns :
n=31+2×(1+2+3+....+31)
n=31+2×(31×32:2)
n=31+2×(992:2)
n=31+2×496
n=31+992
n=1023
n=31+2×(31×32:2)
n=31+2×(992:2)
n=31+2×496
n=31+992
n=1023
n = 31 + 2 x ( 1+2+...+30)
1+2+..+30 = (30 *31) /2
=> n = 31 + 2 * (30*31) / 2
n = 31 + 30 * 31
n = 31 ( 1 + 30)
n = 31 * 31
n = 31^2 care este patrat perfect