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A143273 Triangle read by rows, A127648 * A000012 * A130209, 1<=k<=n. 1
1, 2, 4, 3, 6, 6, 4, 8, 8, 12, 5, 10, 10, 15, 10, 6, 12, 12, 18, 12, 24, 7, 14, 14, 21, 14, 28, 14, 8, 16, 16, 24, 16, 32, 16, 32, 9, 18, 18, 27, 18, 36, 18, 36, 27, 10, 20, 30, 20, 40, 20, 40, 30, 40, 11, 22, 22, 33, 22, 44, 22, 44, 33, 44, 22 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Row sums = A143274: (1, 6, 15, 32, 50, 84,...).

LINKS

Table of n, a(n) for n=1..65.

FORMULA

Triangle read by rows, A127648 * A000012 * A130209, 1<=k<=n.

T(n,k) = n*d(k).

EXAMPLE

First few rows of the triangle =

1;

2, 4;

3, 6, 6;

4, 8, 8, 12;

5, 10, 10, 15, 10;

6, 12, 12, 18, 12, 24;

7, 14, 14, 21, 14, 28, 14;

8, 16, 16, 24, 16, 32, 16, 32;

...

T(6,3) = 12 = 6*d(3) =6*2, where A000005 = d(k) = (1, 2, 3, 2, 2, 4, 2, 4, 3,...)

PROG

(PARI) tabl(nn) = for (n=1, nn, for (k=1, n, print1(n*numdiv(k), ", ")); print(); ); \\ Michel Marcus, Mar 19 2016

CROSSREFS

Cf. A000005, A127648, A130209, A143274.

Sequence in context: A328108 A091850 A245454 * A141429 A309131 A162953

Adjacent sequences:  A143270 A143271 A143272 * A143274 A143275 A143276

KEYWORD

nonn,tabl

AUTHOR

Gary W. Adamson, Aug 03 2008

STATUS

approved

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Last modified December 5 15:11 EST 2019. Contains 329753 sequences. (Running on oeis4.)