What Is The Meaning Of 2,6,5,4,3?

I suppose the above question is about sequences and series. In this particular kind of mathematics. There is a series or a sequence of numbers given. They are arranged in an order so that by adding, multiplying, subtracting or dividing a particular number from the first number of the series you can get the next number and it continues in the same pattern. E.g
1,3,5,7 is a series whereby the numbers are increasing by the number 2.