ABSTRACT
The context of a sequence is the list of parameters used in its definition; in particular it includes the integer k.
Example. Let a and d be two real numbers and let k be a nonnegative integer. We define an arithmetic progression (with common difference d) as follows:
uk = a and un+1 = un + d for n ≥ k. It is immediate that un = a+ (n− k) · d, for all n ≥ k. The parameters of this definition are a, d and k.
