Recurrence relation
= Recurrence relation
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A recurrence relation specifies members of a <sequence> in terms of previous members, together with enough initial values to determine the sequence. A three-term recurrence for <orthogonal polynomials> relates consecutive orders. For example, the physicists' <Hermite polynomials> satisfy $H_{n+1}(x)=2xH_n(x)-2nH_{n-1}(x)$, starting from $H_0=1$ and $H_1=2x$.