A014643 - OEIS

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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.

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

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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