% updown2.m
% up-down algorithm
Nums = 25:50; % numbers to test
for i=1:length(Nums)
N = Nums(i); % number to test
count = 0; % iteration count
while N>1
if rem(N,2)==0 % even
N = N/2;
count = count+1;
else % odd
N = (3*N+1)/2;
count = count+2;
end
end
Counts(i) = count;
end
results = [Nums' Counts']