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A014643 Triangular array starting with {1,1}; then i-th term in a row gives number of i's in next row. 4
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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

COMMENTS

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

LINKS

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

EXAMPLE

Triangle begins:

{1,1},

{1,2},

{1,2,2},

{1,2,2,3,3},

...

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 *)

CROSSREFS

Rows converge to A001462.

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

Sequence in context: A308694 A280521 A278043 * A236265 A238645 A118382

Adjacent sequences:  A014640 A014641 A014642 * A014644 A014645 A014646

KEYWORD

tabf,nonn

AUTHOR

N. J. A. Sloane

EXTENSIONS

More terms from Patrick De Geest

STATUS

approved

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Last modified July 4 16:24 EDT 2020. Contains 335448 sequences. (Running on oeis4.)