I often have to generate a geometric sequence so I created this simple online utility that does it for me. It lets you generate however many geometric series numbers you need in any base. It works in the browser and is powered by alien technology from the future.

Geometric Progression Generator Options

Start and Common Ratio
Count and Separator
Base

Geometric Progression Generator Examples (click to try!)

Geometric Series of Cubes
In this example, we start the geometric series from 1 and calculate 50 of its members. The common ratio for this series is set to 3, which means that each subsequent value in the series is tripled and we get a list of cubes.
1, 3, 9, 27, 81, 243, 729, 2187, 6561, 19683, 59049, 177147, 531441, 1594323, 4782969, 14348907, 43046721, 129140163, 387420489, 1162261467, 3486784401, 10460353203, 31381059609, 94143178827, 282429536481, 847288609443, 2541865828329, 7625597484987, 22876792454961, 68630377364883, 205891132094649, 617673396283947, 1853020188851841, 5559060566555523, 16677181699666569, 50031545098999707, 150094635296999121, 450283905890997363, 1350851717672992089, 4052555153018976267, 12157665459056928801, 36472996377170786403, 109418989131512359209, 328256967394537077627, 984770902183611232881, 2954312706550833698643, 8862938119652501095929, 26588814358957503287787, 79766443076872509863361, 239299329230617529590083
Series starting value.
How many values to generate?
Series common ratio value.
Separate terms with this value.
Decimal Base
Rational Common Ratio
In this example, we use a fractional common ratio of -0.2 for the geometric progression. As the ratio is negative and less than one, we get an alternating (changing sign from minus to plus) and decaying geometric progression.
-1
0.2
-0.04
0.008
-0.0016
0.00032
-0.000064
0.0000128
-0.00000256
0.000000512
Series starting value.
How many values to generate?
Series common ratio value.
Separate terms with this value.
Decimal Base
Hex Geometric Sequence
In this example, we generate a fun geometric sequence in hexadecimal base. We start from 10 (which is "a" in the base 16) and compute the first 20 sequence terms. As the ratio is set to -1, the absolute value of the terms remains unchanged, however the sign changes every time.
a; -a; a; -a; a; -a; a; -a; a; -a; a; -a; a; -a; a; -a; a; -a; a; -a
Series starting value.
How many values to generate?
Series common ratio value.
Separate terms with this value.
Hexadecimal Base

How Does This Geometric Progression Generator Work?

This geometric series generator works entirely in your browser and is written in JavaScript. To get the job done, it uses a single array and a for loop. First, it initializes array with the starting value, which is specified in the options. Then, it creates a for loop with the condition to stop when array reaches count (series length; specified in options) members. In the loop, it keeps track of array's last element, multiplies it by the ratio (common ratio; specified in options), and adds the new term at the end of array by using the array.push() function. To work with large numbers, it uses the bignumber.js library and all multiplication operations are performed by bignumber's times() function. When the loop ends, it array.map()s bignumber's toString(base) function to convert series terms into base (specified in options). After this, it array.join()s all terms with the separator value (sequence value separator; also specified in the options).

Created by Browserling

This geometric progression generator was created by me and my team at Browserling. Behind the scenes, it's actually powered by Browserling's programmer tools that are used by millions of people every month. Browserling itself is an online cross-browser testing service powered by alien technology. Check it out!

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