The n^th term of the sequence is given as a_n= (-1)^n-1 5^{n + 1}

The first five terms of the sequence would be given by putting values of n as 1, 2, 3, 4 and 5

a₁= (-1)^1-1 5^{1 + 1} = (-1)⁰ 5² = 25 (∵ a⁰ =1)

a₂ = (-1)^2-1 5^{2 + 1} = (-1)¹ 5³ = -125

a₃ = (-1) ^3-1 5^{3 + 1} = (-1)² 5⁴ = 625

a₄ = (-1)^4-1 5^{4 + 1} = (-1)³ 5⁵ = -3125

a₅= (-1)^5-1 5^{5 + 1} = (-1)⁴ 5⁶ = 15625

∴ the first five terms of the sequence are 25, -125, 625, -3125 and 15625