This sequence of numbers is called the Fibonacci Numbers or Fibonacci Sequence. The Fibonacci numbers are interesting in that they occur throughout both. Fibonacci Sequence describes the mathematic theory behind the numbers.

The outer ring of ray florets in the daisy family illustrate the Fibonacci sequence extremely well. Daisies with 13, 21, 34, 55 or 89 petals are quite. Can you predict what the next numbers will be in each of these strings of digits?

123454321234543212...
11235813213455...
993751058209749...

The first sequence has a clear rhythm to it. The second is a little more tricky, but look closely and you might notice that it uses the previous numbers in the string to build the next one. This is the Fibonacci sequence, nature's favourite set of numbers and the first code to be cracked in Dan Brown's The Da Vinci Code. The third sequence is much trickier.

At first it looks random but if you come at it armed with the right knowledge you might recognise that it is part of the decimal expansion of pi, starting at the 44th decimal place. Once you know this you have total control over the sequence and can predict every twist as it speeds off to infinity.

Using Fibonacci sequences in knitting or weaving patterns.

Mathematics is all about spotting patterns, finding the underlying logic in the seemingly random and chaotic world around us; and using this information to predict future behaviour. Traditionally maths has been used to make predictions about inanimate objects, like the orbit of planets or the weather. But as Stephen Baker explains in The Numerati, mathematicians are increasingly turning their attention to human behaviour.

What if those strings of numbers are records of the things you've bought, places you've travelled to, websites you've visited, parties you've voted for? Fibonacci sequences? Find the pattern in the numbers and mathematicians will be able to predict, with surprising accuracy - what your next move will be. The 'numerati' is the name Baker gives to the group of latterday fortune-tellers whose job it is to decode our behaviour. His book explores the lives of such people and attempts to analyze how powerful they have become.

The Fibonacci numbers are the sequence of numbers {F_n}_(n=1)^infty defined by the linear recurrence equation
F_n=F_(n-1)+F_(n-2) (1)

with F_1=F_2=1. As a result of the definition (1), it is conventional to define F_0=0.

The Fibonacci numbers for n=1, 2, ... are 1, 1, 2, 3, 5, 8, 13, 21, ... (Sloane's A000045).

Fibonacci numbers can be viewed as a particular case of the Fibonacci polynomials F_n(x) with F_n=F_n(1).

Fibonacci numbers are implemented in Mathematica as Fibonacci[n].

The Fibonacci numbers are also a Lucas sequence U_n(1,-1), and are companions to the Lucas numbers (which satisfy the same recurrence equation).

For those with the ability to interpret it, this data trail is a goldmine. Advertisers and politicians have long dreamed of being able to target their messages - or products - at individuals on the basis of highly detailed information about them. Now this dream is becoming reality. By analysing the geometry of our mathematical pathways, mathematicians can cluster people with shared interests and passions, creating ever smaller, more specific groups to target.

For example, Baker talks to one of the numerati, Dave Morgan of AOL, who picked up a correlation between people visiting the Alamo Rent A Car website and surfing romantic movie sites. It isn't an obvious match; only in retrospect could it be traced to an escapist tendency. But once the pattern was identified, advertisers could find all sorts of clever ways to exploit it - for example, by bombarding this particular group with offers for weekend breaks in country hotels.

Baker argues that the numerati have become incredibly powerful in a range of fields, from the workplace to the voting booth, from health care to counter-terrorism. He even puts the maths to the test to see if a dating agency can pair him with his wife; when he eventually unchecks the box requesting someone several decades too young, Mrs Baker pops up top of the list. There is no denying that the digital revolution has opened up exciting new territory for mathematicians. The numerati are no fantasy; they exist. Baker is telling us about a phenomenon that is important and often overlooked. That makes his book urgent and exciting.

Until recently, the abstract language of mathematics seemed to have no relevance to the murky worlds of consumer trends, political preferences and dating. The change that has made the rise of the numerati possible is digitization. All of us today leave an extensive trail of numbers wherever we go. Almost everything we do - from visiting a website to texting a friend - is translated into ones and zeros, which are stored somewhere and available to those who know how to access them. For example, every time we enter a search into Google, a simple code called ASCI translates each letter we type into a string of 0s and 1s, which are sent out across the internet.

When we unload our shopping trolleys at the checkout, the bar codes of our purchases are stored by our loyalty cards, providing a record of our eating habits. When we walk down the road, our movements are likely to be tracked by CCTV, converted into digital code and stored on computer mainframes. Even our moods and thoughts get translated into zeros and ones by the technology we love and rely on, as thousands of us pour our states of minds on to blogs. Forget astrology and the stars; your future is encoded within the trail of numbers that you leave behind you.