Arithmetic, geometric and other sequences
Each term = previous + d
Sn = n(a1 + an)/2
Each term = previous × q
Sn = a1(1 - qⁿ)/(1 - q)
S = a1/(1-q) when |q| < 1
1 + 1/2 + 1/3 + ... diverges
When a sequence has a limit
Fibonacci sequence and φ = 1.618...
Series of the form Σ aₙ xⁿ
Infinitely many steps = finite distance