arithmetic sequence formula
where,
a_n=the nᵗʰ term in the sequence
a_1=the first term in the sequence
d=the common difference between terms
n = term position
For the following sequence: 1, 5, 9, 13,...
a_1=the first term in the sequence = 1
d=the common difference between terms = 4
therefore, a general formula for this sequence woul be: