41. RATTLE PRIMES LIKE RAMANUJAN?
 
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Prime numbers have no 'factors'.
They form an important part of 'Theory of Numbers' in Mathematics.

It is said,
Ramanujan could rattle primes upto a crore
(1 00 00 000, 1 koti or 10 million).


Become Ramanujan!
If not so many like Ramanujan, it is good to know atleast a few primes.
Any one can easily work-out and remember primes below 100.
How many primes can you rattle?

Let us 'work' the Primes below 100
a) 1 is not a prime (nor a composite).
b) Evens are not primes (except 2).
c) Multiples of 5, like 15, 25, 35, ... are not primes.
d) So primes end only in 1, 3, 7 or 9.
e) The first four primes 2, 3, 5, 7 are exceptions.
    They do not follow any pattern.

We shall list the primes in 10 rows of 4 columns.
We shall test the primality by dividing by 3 and 7.
In fact, it is enough to test numbers upto 120 by 3 and 7.

You should work out the primes yourself and verify.

2357 

11131719 
 23 29 
31 37  
414347  

 53 59 
61 67  
7173 79 
 83 89 
  97  



Did you notice there are 25 primes below 100 and of these 15 are below 50?

If you are interested in rattling at least these 25 primes, then you may learn (memorise) just one row of primes each day.
This takes just 10 days.
Then you also can rattle these primes!

You may also work out more primes 'this way'.