til¶ First x natural numbers til x til[x] Where x is a non-negative integer atom, returns a vector of the first x integers. q)til 0 `long$() q)til 1b ,0 q)til 5 0 1 2 3 4 q)til 5f 'type [0] til 5f ^ til and key are synonyms, but the above usage is conventionally reserved to til. Mathematics