A127445 Triangle defined by the matrix product A126988 * A127368, read by rows.

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

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: A306562 A351190 A131486 * A324025 A081170 A201291

Adjacent sequences: A127442 A127443 A127444 * A127446 A127447 A127448

Keyword

nonn,tabl

Author

Gary W. Adamson, Jan 14 2007

Status

approved