编辑代码

program seq
    implicit none
    integer :: i
    real :: a, b, c, d

    a = 0
    b = 0
    c = 1

    print *, a
    print *, b
    print *, c

    do i = 4, 20
        d = a + b + c
        a = b
        b = c
        c = d
        print *, d
    end do

end program seq