Factor T was created in 1956.
The 'Human' Factor was created in 1975.
Given I<T, the accumulation factor A(I,T) is the accumulation value at the time T of one unit of money invested at time I. So for compound interest A(I,T)= (1+i)^(T-I).
T(t + 4)
The Zoya Factor was created in 2008.
The Ascension Factor was created in 1988.
The Fizz Factor was created in 2002.
The Dreadnaught Factor was created in 1983.
The Alien Factor was created in 1976.
The XY Factor was created in 2002.
The Trygon Factor was created in 1966.
The Dalek Factor was created in 2004.
The Radio Factor was created in 2002.