A127447 - OEIS

A127447

Triangle defined by the matrix product A127446 * A054521, read by rows 1<=k<=n.

1, 4, 0, 6, 3, 0, 12, 0, 4, 0, 10, 5, 5, 5, 0, 24, 6, 0, 0, 6, 0, 14, 7, 7, 7, 7, 7, 0, 32, 0, 16, 0, 8, 0, 8, 0, 27, 18, 0, 9, 9, 0, 9, 9, 0, 40, 10, 20, 10, 0, 0, 10, 0, 10, 0, 22, 11, 11, 11, 11, 11, 11, 11, 11, 11, 0, 72, 12, 12, 0, 24, 0

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OFFSET

1,2

LINKS

Table of n, a(n) for n=1..72.

FORMULA

T(n,k) = Sum_{j=k..n} A127446(n,j) * A054521(j,k).

EXAMPLE

First few rows of the triangle are:

4, 0;

6, 3, 0;

12, 0, 4, 0;

10, 5, 5, 5, 0;

24, 6, 0, 0, 6, 0;

14, 7, 7, 7, 7, 7, 0;

32, 0, 16, 0, 8 0, 8, 0;

...

MAPLE

A054521 := proc(n, k) if igcd(n, k) = 1 then 1; else 0; fi; end:

A127447 := proc(n, k)

add( A127446(n, j)*A054521(j, k), j=k..n) ;

end proc:

seq(seq(A127447(n, m), m=1..n), n=1..12) ; # R. J. Mathar, Nov 08 2011

CROSSREFS

Cf. A038040 (column k=1), A000290 (row sums), A127446, A054521.

Sequence in context: A378333 A200692 A360044 * A226775 A338682 A305731

Adjacent sequences: A127444 A127445 A127446 * A127448 A127449 A127450

KEYWORD

nonn,tabl

AUTHOR

Gary W. Adamson, Jan 14 2007

STATUS

approved