Help correcting the sequence function

Hello , i was wondering if anyone could help me out a little bit , so am writing a function ,which calculates sequence in a matrix diaognaly , but am little bit stuck ,its not givng the numbers that i want

n=input('sequence_matrix_')
fibb=[1,3:n];
for i=3:n
fibb(i)=fibb(i-1)*3+1;
end
(fibb)

I want it to display

1,3,10,33,109,360

Answer 1

[DGM]

% if you're asking the user for a number, use a clear description
% "sequence matrix" doesn't tell anyone what the number means
n = 10; % number of elements in sequence

fibb = zeros(1,n);
fibb(1:2) = [1 3]; % only the first two numbers are used
for i = 3:n
    fibb(i) = fibb(i-1)*3 + fibb(i-2); % only +1 for first iteration
end
fibb

fibb = 1×10

1 3 10 33 109 360 1189 3927 12970 42837