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A127445 Triangle defined by the matrix product A126988 * A127368, read by rows. 1
1, 3, 0, 4, 2, 0, 7, 0, 3, 0, 6, 2, 3, 4, 0, 12, 4, 0, 0, 5, 0, 8, 2, 3, 4, 5, 6, 0, 15, 0, 9, 0, 5, 0, 7, 0, 13, 8, 0, 4, 5, 0, 7, 8, 0, 18, 4, 9, 8, 0, 0, 7, 0, 9, 0, 12, 2, 3, 4, 5, 6, 7, 8, 9, 10, 0, 28, 8, 9, 0, 15, 0, 7, 0, 0, 0, 11 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..77.

FORMULA

T(n,k) = Sum_{j=k..n} A126988(n,j) * A127368(j,k), 1<=k<=n.

EXAMPLE

First few rows of the triangle are:

1;

3, 0;

4, 2, 0;

7, 0, 3, 0;

6, 2, 3, 4, 0;

12, 4, 0, 0, 5, 0;

8, 2, 3, 4, 5, 6, 0;

...

MAPLE

A127368:=proc(n, k) if igcd(n, k) = 1 then k else 0 fi end:

A127445 := proc(n, k)

        add (A126988(n, j)*A127368(j, k), j=k..n) ;

end proc:

seq(seq(A127445(n, k), k=1..n), n=1..14) ; # R. J. Mathar, Nov 11 2011

CROSSREFS

Cf. A126988, A127368, A000217 (row sums), A000203 (column k=1).

Sequence in context: A003815 A306562 A131486 * A324025 A081170 A201291

Adjacent sequences:  A127442 A127443 A127444 * A127446 A127447 A127448

KEYWORD

nonn,tabl

AUTHOR

Gary W. Adamson, Jan 14 2007

STATUS

approved

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Last modified June 23 13:59 EDT 2021. Contains 345402 sequences. (Running on oeis4.)