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A137679 Triangle read by rows, A000012 * A008284. 2
1, 2, 1, 3, 2, 1, 4, 4, 2, 1, 5, 6, 4, 2, 1, 6, 9, 7, 4, 2, 1, 7, 12, 11, 7, 4, 2, 1, 8, 16, 16, 12, 7, 4, 2, 1, 9, 10, 23, 18, 12, 7, 4, 2, 1, 10, 25, 31, 27, 19, 12, 7, 4, 2, 1, 11, 30, 41, 38, 29, 19, 12, 7, 4, 2, 1, 12, 36, 53, 53, 42, 30, 19, 12, 7, 4, 2, 1 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Row sums = A026905: (1, 3, 6, 11, 18, 29,...). Rows tend to A000070 starting from the right: (1, 2, 4, 7, 12, 19, 30,...).

LINKS

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

FORMULA

A000012 * A008284 as infinite lower triangular matrices.

EXAMPLE

First few rows of the triangle are:

1;

2, 1;

3, 2, 1;

4, 4, 2, 1;

5, 6, 4, 2, 1;

6, 9, 7, 4, 2, 1;

7, 12, 11, 7, 4, 2, 1;

8, 16, 16, 12, 7, 4, 2, 1;

...

CROSSREFS

Cf. A008284, A026905, A000070.

Sequence in context: A064881 A131967 A300670 * A152072 A105438 A062001

Adjacent sequences:  A137676 A137677 A137678 * A137680 A137681 A137682

KEYWORD

nonn,tabl

AUTHOR

Gary W. Adamson, Feb 05 2008

STATUS

approved

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Last modified July 20 22:20 EDT 2019. Contains 325189 sequences. (Running on oeis4.)