# Fibonacci sequence, slightly different.

3 views (last 30 days)
Bob Whiley on 19 Feb 2015
Edited: Bob Whiley on 19 Feb 2015
I am trying to write a code for the fibonacci sequence, but instead of adding the the term to its previous one, I want a number to start with (say 4, my code input called begin) and its first two outputs would be 4. It would loop n times (say 7 for this example). The output would look like [4 4 8 12 16 20 24]. How could I generalize this. So far I have
if begin ~=1 || begin ~= 0
seq(1)=begin;
seq(2)=begin;
k=3;
while k <= n
seq(k)=seq(begin-1)+begin;
k =k+1;
end
end

James Tursa on 19 Feb 2015
Looks like your indexing into seq is not quite right. Try this:
seq(k)=seq(k-1)+begin;
Bob Whiley on 19 Feb 2015
Perfect, thanks!

Titus Edelhofer on 19 Feb 2015
Hi,
I don't see what this has to do with Fibonacci though ;-). But you don't need the loop, just do something like
seq = begin * [1 1:(n-1)];
Titus

Evan on 19 Feb 2015
Edited: Evan on 19 Feb 2015
It seems to be quite close. You just need to make one small change. You should reference the seq variable using the index, k, not the begin variable:
begin = 4;
n = 5;
if begin ~=1 && begin ~= 0
seq(1)=begin;
seq(2)=begin;
k=3;
while k <= n
seq(k)=seq(k-1)+seq(k-2);
k = k+1;
end
end
Note that your example output isn't a fibonnaci sequence. Is this really what you want? If so, you could just make that array with:
begin = 4;
n = 5;
seq = [begin begin:begin:begin * n];

Bob Whiley on 19 Feb 2015
Edited: Bob Whiley on 19 Feb 2015
If he beginning number were 0, how could I make it so the first index in the output vector is 0, then the sequence continues normally after. Like if n = 6, and begin = 0, how could I get the output [0 1 1 2 3 5]
What I have so far is
if begin == 0
seq(1)=1;
seq(2)=1;
k=3;
while k <= n
seq(k)=seq(k-1)+seq(k-2);
k=k+1;
end
end

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