Work out nth term of a sequence instantly with clear inputs, formula shown and shareable results.
An arithmetic sequence adds a fixed difference, giving aₙ = a + (n − 1)d. A geometric sequence multiplies by a fixed ratio, giving aₙ = a·r^(n−1). Both count the first term as n = 1.
Arithmetic nth term
aₙ = a + (n − 1)d
Geometric nth term
aₙ = a · r^(n−1)
5 + 11 × 3 = 38.
Because the first term needs no steps added, so the number of steps to term n is one fewer than n.