A131818 A130296 + A002260 - A000012. Triangle read by rows: row n consists of n, 2, 3, 4, ..., n.

1, 2, 2, 3, 2, 3, 4, 2, 3, 4, 5, 2, 3, 4, 5, 6, 2, 3, 4, 5, 6, 7, 2, 3, 4, 5, 6, 7, 8, 2, 3, 4, 5, 6, 7, 8, 9, 2, 3, 4, 5, 6, 7, 8, 9, 10, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12

Offset

1,2

Comments

Row sums = A034856; (1, 4, 8, 13, 19, 26, 34, ...).

Links

Table of n, a(n) for n=1..78.

Formula

A130296 + A002260 - A000012 as infinite lower triangular matrices.

T(n, 1) = n, T(n, k) = k for k > 1. - Michel Marcus, Feb 12 2014

Example

First few rows of the triangle:
  1;
  2, 2;
  3, 2, 3;
  4, 2, 3, 4;
  5, 2, 3, 4, 5;
  6, 2, 3, 4, 5, 6;
  7, 2, 3, 4, 5, 6, 7;
  ...

Mathematica

Table[Join[{n}, Range[2, n]], {n, 15}]//Flatten (* Harvey P. Dale, Feb 24 2021 *)

Prog

(PARI) t(n, k) = if (k==1, n, k); \\ Michel Marcus, Feb 12 2014

Crossrefs

Cf. A130296, A002260, A034856.

Sequence in context: A338283 A104324 A193212 * A222111 A222438 A222027

Adjacent sequences: A131815 A131816 A131817 * A131819 A131820 A131821

Keyword

nonn,tabl

Author

Gary W. Adamson, Jul 18 2007

Extensions

More terms from Michel Marcus, Feb 12 2014

Status

approved