A for loop as per KSSV's answer is probably the best way to do this.
cell2mat(arrayfun(@(s,e) s:e, IND(:, 1), IND(:, 2), 'UniformOutput', false)')
would be one way to do it without a loop, if you consider arrayfun not to be a loop. It's more likely to be slower than an actual for loop.
See also my old cody problem which asks to do just the same. For information, the best scoring solution is:
str2num(sprintf('%d:%d ', IND'))
whose only merit is that it is low scoring on cody. Certainly don't use that for real code, it's going to be very slow.
