A014643 Triangular array starting with {1,1}; then i-th term in a row gives number of i's in next row.

1, 1, 1, 2, 1, 2, 2, 1, 2, 2, 3, 3, 1, 2, 2, 3, 3, 4, 4, 4, 5, 5, 5, 1, 2, 2, 3, 3, 4, 4, 4, 5, 5, 5, 6, 6, 6, 6, 7, 7, 7, 7, 8, 8, 8, 8, 9, 9, 9, 9, 9, 10, 10, 10, 10, 10, 11, 11, 11, 11, 11

Offset: 1

Author

N. J. A. Sloane

Keywords

• tabf
• nonn

Comments

The row {2} could be safely prepended to this triangle. - Gus Wiseman, May 13 2018

Examples

			Triangle begins:
{1,1},
{1,2},
{1,2,2},
{1,2,2,3,3},
...
		

Links

• Alois P. Heinz, Rows n = 1..8, flattened

Crossrefs

Rows converge to A001462.

Cf. A011784, A012257, A014643, A014644, A112798, A181819, A182850-A182858, A296150, A304455.

Programs

Maple

T:= proc(n) option remember; `if`(n=0, 2, (l->
      seq(i$l[i], i=1..nops(l)))([T(n-1)]))
    end:
seq(T(n), n=1..7);  # Alois P. Heinz, May 17 2018

Mathematica

NestList[Join@@Table[Table[i,{#[[i]]}],{i,Length[#]}]&,{2},8] (* Gus Wiseman, May 13 2018 *)

Extensions

More terms from Patrick De Geest