Spot the next number: 2, 6, 12, 20, 30… The gaps are 4, 6, 8, 10 — growing by 2 each time — so the next gap is 12 and the next term is 42. That little dopamine hit is pattern recognition, and sequences formalize it: arithmetic sequences add a constant, geometric sequences multiply by a constant, and quadratic sequences have gaps that themselves form a pattern. IQ tests, puzzle books, and job aptitude screens all probe exactly this skill.

Beyond puzzles, sequences model the world. Rabbit populations multiply geometrically, loan balances shrink geometrically with payments, and the triangular numbers 1, 3, 6, 10 count handshakes in a group. Programmers generate sequences for test data; quilters and tilers lay them out in fabric and floor patterns. This calculator evaluates sequence arithmetic: enter the known anchor term and the pattern's step contribution and it returns the computed term — verify your spotted pattern produces consistent values before committing to an answer.

With the pre-filled defaults — Variable A 10, Variable B 5 — the Number Sequence Calculator returns Result 50.0000. Change any input and those results update instantly, so you can see exactly how each number you enter moves the answer.