A127466 Triangle read by rows: A054525 * A127481 as infinite lower triangular matrices.

1, 2, 2, 3, 0, 6, 4, 4, 0, 8, 5, 0, 0, 0, 20, 6, 6, 12, 0, 0, 12, 7, 0, 0, 0, 0, 0, 42, 8, 8, 0, 16, 0, 0, 0, 32, 9, 0, 18, 0, 0, 0, 0, 0, 54, 10, 10, 0, 0, 40, 0, 0, 0, 0, 40

Offset

1,2

Comments

Mobius transform of A127481.

Links

Table of n, a(n) for n=1..55.

Formula

Sum_{k=1..n} T(n,k) = n^2.

T(n,n) = A002618(n) = n*phi(n).

Example

First few rows of the triangle are:
1;
2, 2;
3, 0, 6;
4, 4, 0, 8;
5, 0, 0, 0, 20;
6, 6, 12, 0, 0, 12;
7, 0, 0, 0, 0, 0, 42;
8, 8, 0, 16, 0, 0, 0, 32;
...

Maple

A127466 := proc(n, k)
    add( A054525(n, j)*A127481(j, k), j=k..n) ;
end proc: # R. J. Mathar, Sep 06 2013

Crossrefs

Cf. A054522, A127093, A062952, A002618.

Cf. A127093, A127481, A054525.

Sequence in context: A199784 A376931 A349384 * A342314 A099118 A320999

Adjacent sequences: A127463 A127464 A127465 * A127467 A127468 A127469

Keyword

nonn,tabl

Author

Gary W. Adamson, Jan 15 2007

Extensions

Edited by N. J. A. Sloane at the suggestion of Andrew S. Plewe, Aug 23 2007

Status

approved