A128219 - OEIS

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A128219

A000012 * A127701. a(1) = 1, a(2) = 2, a(3) = 2; by rows, n-1 terms of 2, 3, 4, ... followed by "n".

1

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

(list; table; graph; refs; listen; history; text; internal format)

OFFSET

1,2

LINKS

Table of n, a(n) for n=1..83.

FORMULA

A000012 * A127701 as infinite lower triangular matrices.

EXAMPLE

First few rows of the triangle:

1;

2, 2;

2, 3, 3;

2, 3, 4, 4;

2, 3, 4, 5, 5;

2, 3, 4, 5, 6, 6;

2, 3, 4, 5, 6, 7, 7;

...

MATHEMATICA

trm[i_]:=Join[Range[2, i], {i}]; Flatten[Table[trm[n], {n, 13}]] (* Harvey P. Dale, Nov 14 2012 *)

CROSSREFS

Cf. A000012, A127701, A034856 (row sums), A128220.

Sequence in context: A094528 A077774 A344150 * A238969 A238956 A331415

Adjacent sequences: A128216 A128217 A128218 * A128220 A128221 A128222

KEYWORD

nonn,tabl

AUTHOR

Gary W. Adamson, Feb 19 2007

STATUS

approved