Explanation:
The formula for the nth term of an arithmetic sequence is:
a_n = a + (n - 1)d
where a is the first term, d is the common difference, and n is the term number.
Substituting a=1 and d=5, we get:
a_n = 1 + (n - 1)5
Simplifying this expression, we get:
a_n = 5n - 4
Therefore, the formula for the nth term of the arithmetic sequence with first term a=1 and common difference d=5 is a_n = 5n - 4.