A127627 Triangle T(n,k) = A054525(n,k)*A018804(k), read by rows 1<=k<=n.

1, -1, 3, -1, 0, 5, 0, -3, 0, 8, -1, 0, 0, 0, 9, 1, -3, -5, 0, 0, 15, -1, 0, 0, 0, 0, 0, 13, 0, 0, 0, -8, 0, 0, 0, 20, 0, 0, -5, 0, 0, 0, 0, 0, 21, 1, -3, 0, 0, -9, 0, 0, 0, 0, 27, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 21, 0, 3, 0, -8, 0, -15, 0, 0, 0, 0, 0, 40

Offset

1,3

Links

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

Formula

T(n,1) = A008683(n).

T(n,n) = A018804(n).

Example

First few rows of the triangle are:
1;
-1, 3;
-1, 0, 5;
0, -3, 0, 8;
-1, 0, 0, 0, 9;
1, -3,-5, 0, 0, 15;
...

Maple

A018804 := proc(n)
    sum(igcd(n, j), j=1..n):
end proc:
A127627 := proc(n, k)
    A054525(n, k)*A018804(k) ;
end proc: # R. J. Mathar, Oct 21 2012

Crossrefs

Cf. A054525, A018804, A029935 (row sums).

Sequence in context: A045406 A143468 A133728 * A154792 A185911 A187954

Adjacent sequences: A127624 A127625 A127626 * A127628 A127629 A127630

Keyword

tabl,easy,sign

Author

Gary W. Adamson, Jan 20 2007

Status

approved