samer@0: function y=expdata(A,B,N,M)
samer@0: % expdata - exponential data sequence
samer@0: %
samer@0: % expdata :: 
samer@0: %    real  ~'initial value',
samer@0: %    real  ~'final value',
samer@0: %    natural ~'number of steps (sequence length is steps+1),
samer@0: %    M:natural ~'buffer size'
samer@0: % -> seq [[1,M]].
samer@23: lA=log(A);
samer@23: k=(log(B)-lA)/N;
samer@23: y=map(@(i)exp(lA+k*i),integers(0,N));