Hello from MrBillDoesMath!
Answer:
2, 10, 50, 250
Discussion:
a(n) = 2*(5)^(n-1) n = 1,2,3..
So
a(1) = 2 * (5^0) = 2 * 1 = 2
a(2) = 2* (5)^(2-1) = 2 *5 = 10
a(3) = 2 * (5)^(3-1) = 2 * 5^2 = 2 * 25 = 50
a(4) = 2 * (5)^(4-1) = 2 * 5^3 = 2 * 125 = 250
Thank you,
MrB