It is a six-digit whole number. It has only three different digits, each used twice.
The sum of its different digits is 24.
It is divisible by 4.
It is greater than 800,000.
Its ten-thousands digit is different from its hundred-
thousands digit.
Its thousands digit is the same as its ten-thousands
digit.
Its tens digit is the same as its ones digit.
Its tens digit is different from its hundreds digit.
Its hundreds digit is 9.

, and

for

step-by-step explanation:

we can analyze the pattern at which the terms increase. let us denote , , , so that we can call

note the following:

the pattern: to get the next term value, we just add the next term number (e.g. 1st, 2nd, to the previous term value (term values are the given numbers in the question, 1, 3, 6, 10, 15,

from , to get to , we add

from , to get to , we add

etc.

we need to form a recursive formula, a formula that has the next term as a function of the previous term. so a possible recursive formula can be

, and for

hope this is what you were asking for!

step-by-step explanation: