Knowledge Node - Sequences

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Definition. A sequence, unlike a set, is an ordered, countable collection of values. Basically, a sequence is a function mapped from the natural numbers to the real numbers. A sequence is denoted as

{an} = (an)n = (an) , where n is the nth term in the sequence.

Ex. Here are some example sequences. By themselves they aren't that interesting, but as always, there's more to study...

The Harmonic Sequence: (an)n = (1/n)n = ( 1, 1/2, 1/3, 1/4, 1/5, ... )

Reciprocal Squares: (an)n = (1/(n2))n = ( 1, 1/4, 1/9, 1/16, ... )

Geometric Sequence (an)n = (a/(rn))n = ( a, a/r, a/r2, a/r3, ... )

I always thought it was important for a sequence to start at index 1, but apparently, the geometric sequence starts at 0. I'm sure others can start at 2, or any number you want for that matter.

just curious... added 5/4/04

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