Number Sequence Calculator
There are many different types of number sequences. The following are calculators for some of them.
Reference
By definition, a sequence is an ordered list of objects. Accordingly, a number sequence is an ordered list of numbers. Many different types of number sequences have been invented. We have calculators for the following three most common number sequences:
Arithmetic Sequence
An arithmetic sequence is a number sequence that the difference of any two successive numbers is a constant. The following is the formula:

f_{n} = f_{n1} + f
or
a, a + f, a + 2f, a + 3f, a + 4f, ...

1, 3, 5, 7, 9 11, 13, ...

n(f_{1} + f_{n})/2
or
an + n(n1)/2
Geometric Sequence
A geometric sequence is a number sequence that each number after the first is the multiplication of the previous one with a fixed nonzero number. The following is the formula:

f_{n} = f_{n1} * r
or
a, ar, ar^{2}, ar^{3}, ar^{4}, ...

a is a scale factor
r is the common ratio

1, 2, 4, 8, 16, 32, 64, 128, ...

a(1r^{n+1})/(1r)

a^{n}r^{(n(n1)/2)}
Fibonacci Sequence
The Fibonacci sequence is a number sequence that the first two numbers are 0 and 1, and each subsequent number is the sum of the previous two. The following is the formula:
f_{0} = 0
f_{1} = 1
f_{n} = f_{n1} + f_{n2}

0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, ...