It is an arithmetic sequence for which the index goes on and on (and on).
That's an arithmetic sequence.
Arithmetic
From the information given, all that can be said is that it will be a negative number.
You didn't say the series (I prefer to use the word sequence) of even numbers are consecutive even numbers, or even more generally an arithmetic sequence. If we are not given any information about the sequence other than that each member happens to be even, there is no formula for that other than the fact that you can factor out the 2 from each member and add up the halves, then multiply by 2: 2a + 2b + 2c = 2(a + b + c). If the even numbers are an arithmetic sequence, you can use the formula for the sum of an arithmetic sequence. Similarly if they are a geometric sequence.
-161.
When quantities in a given sequence increase or decrease by a common difference,it is called to be in arithmetic progression.
origin of arithmetic sequence
The answer depends on what the explicit rule is!
The given sequence (7, 14, 21, 28, 35,....) is an arithmetic sequence where each term increases by 7. The nth term of the given sequence is 7n
It is an arithmetic sequence for which the index goes on and on (and on).
An arithmetic sequence is a list of numbers which follow a rule. A series is the sum of a sequence of numbers.
That's an arithmetic sequence.
It is the start of an arithmetic sequence.
Arithmetic
Any pair of numbers will always form an arithmetic sequence.
From the information given, all that can be said is that it will be a negative number.