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\(\displaystyle T_{n} = 2n\)
The small n next to the variable T is called a
subscript. It's used to indicate a number's position, in a list of numbers.
Unless you're told otherwise, n represents the Natural numbers {1, 2, 3, ...}
\(\displaystyle T_{16}\) is the 16th number, in the list.
\(\displaystyle T_{453}\) is the 453rd number, in the list, and so on.
To calculate the actual values of these numbers, you substitute a value for n in the expression 2n.
\(\displaystyle T_{16} = 2(16) = 32\)
\(\displaystyle T_{453} = 2(543) = 1086\)
That's about it. Are you good to go?
Cheers :cool: