This works too: (%i1)f(x):=x^2$ ????? m: [0,0,0,0,0]$ ????? for i: 1 thru 5 do m[i]: [i,f(i)]$ ????? m; (%o4) [[1,1],[2,4],[3,9],[4,16],[5,25]] ... except you have to "pre-declare" m to the right size or it won't work.