A048220 a(n)=least m such that column m of T contains n, array T given by A048212.
1, 1, 2, 1, 2, 1, 3, 1, 1, 2, 3, 1, 4, 2, 1, 1, 2, 3, 4, 1, 5, 1, 3, 1, 1, 1, 4, 5, 3, 6, 2, 1, 1, 1, 4, 3, 1, 1, 5, 6, 1, 7, 3, 4, 1, 2, 1, 1, 2, 5, 3, 4, 1, 6, 7, 1, 8, 3, 1, 5, 1, 1, 4, 1, 2, 6, 2, 1, 1, 7, 8, 5, 9, 1, 3, 1, 1, 1, 2, 6, 1, 4, 3, 1, 5, 7, 1, 1, 1, 8
Offset: 1