
Sequence: A sequence is a number pattern in a definite order following a certain rule. It can be denoted by: a_{1}, a_{2}, a_{3}, a_{4}, a_{5} ..........a_{n1}, a_{n} Series: Series is a sum of terms in a sequence. It can be denoted by: a_{1} + a_{2} + a_{3} + a_{4} + a_{5} ..........a_{n1} + a_{n} Series/Sequence are of two types: arithmetic and geometric.
Sequences and series can be finite or infinite. A finite sequence/series is one that eventually comes to an end. Infinite sequences/series are those that continue indefinitely. 