Ok, this will be my last post as I have reached five posts already. This blog post willl be dedicated fully to math and I will not make it very long as I still have homework like the IS final project, chinese worksheet which I unfortunately left at school because of that super-hectic 30 minutes which I covered on the previous post which might take you 30 minutes to read it (for some reason I am a more long-winded bloger than Darrel who is more popular in the long-winded olympics. But let me assure you, I will be a worthy opponent so watch out, Darrel!!). What a coincidence. Anyway, how ironic as I am the Chinese rep. I think I am like the most forgetful chinese rep around. ANYWAY, i HAVE deviated from the topic of math so let us start on it!

Firstly, the answer to the question. As you ave seen, the sequence is 19, 4, 1, 4, 7 and the 6th term is 4 so this is similar to Mr Tan's pattern of 5 '1's. You can therefore see that the repeating fours is an indication of the nth term being something+4. And since this occurence only appears at the 2nd,4th and 6th term, you can safely assume that the nth term is something like (n-6)(n-4)(n-2). However, if you try that, you will get a sequence of -11, 4, 7, 4, 1,4 which is quite different. So the trick is that you have to minus the 4 away from all the terms first. you will then get 15,0,-3,0,3,0. It is then suddenly obvious that this sequence is actually the negated version of your (n-6)(n-4)(n-2) which is equal to a sequence of -15, 0, 3, 0, -3, 0. So, it is now obvious that the nth term is actually (6-n)(4-n)(2-n)+4.

There you have it! And so since I promised to make this short, this post ends here.

Yi Pin.

PS.a maths question for math enthusiasts:another sequence---28,24,12,6,4,?