The difference is the number in front of n
4, 7, 10, 13 goes up by 3, so the rule starts 3n. 3n gives 3, 6, 9 … — one less than each term, so the rule is 3n + 1.
Sequences 🔢
Type the first few terms to find the nth term with the working, or type a rule to get the terms. Linear sequences are drawn as growing patterns, like matchstick squares.
nth term
Linear & quadratic
Matchstick patterns
Nothing leaves your device
nth term
Working
Good to know
Term-to-term or position-to-term?
"Add 3" tells you the next term, but you need every term before it. The nth term jumps straight to the 100th: 3 × 100 + 1 = 301.
Nothing leaves your device
Everything is worked out in your browser and nothing is saved. The address bar keeps the sequence, so a link opens the same working.
Tool created by
លោក ណាត ប៊ុនឆ័យ · Mr. Nat Bunchhai
Alpha Academy Cambodia
Spotting patterns is real mathematics.
Our tutors help students move from patterns to algebra — the step that unlocks the rest of secondary maths.