Here are the first 5 terms of a quadratic sequence.
2 10 22 38 58
Verify that an expression, in terms of nnn, for the n n\,nth term of this sequence is 2n2+2n−22n^2 + 2n - 22n2+2n−2.
201 exam-style questions on Eduqas GCSE Maths The Nth Term of a Quadratic Sequence. Each one has a worked solution and a mark scheme showing where the marks go.