Question

Write a for-loop in MATLAB that generates a list of numbers such that each number is the sum of the previous three. Initialize your list of numbers at the values of 0, 0 and 1. In other words, "0" is the first element of the list, "0" is the second element of the list, and "1" is the third element of the list. What is the 20th value in the list?

Answer 1

function x = sum_of_previous_three (x0,x1,x2)
x = zeros(1,20);
x(1) = x0 ;
x(2) = x1 ;
x(3) = x2 ;
for i = 4 : 20
    x (i) = x(i-1) + x(i-2) + x(i-3);
end

x(20)

// this function takes the first three value as input

sum_of_previous_three(0,0,1)

ans =

       19513

ans =

Columns 1 through 11

           0           0           1           1           2           4           7          13          24          44          81

Columns 12 through 20

         149         274         504         927        1705        3136        5768       10609       19513

20th number is 19513

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