The equation to find the nth term is:
an = a+(n-1)d
Where a is the first term in the sequence, which is 1 and d is the difference, which in this sequence the next term is found by adding 2 to the previous term, so d = 2 and n is the term you want to find.
The equation is:
an = 1 + (n-1)2
a24 = 1 + (24-1)2 = 1 + 23(2) = 1+46 = 47