Pentabonacci Numbers

p5 = [0, 1, 1, 2, 4]

function pn(n::Int64)
    z = Array{BigInt}(undef, n)
    z[1:5] = p5

    for i = 6:n
        z[i] = sum(z[i-5:i-1])
    end

    return z
end