A127470 Triangle equal to the matrix product A127466 * A051731.

1, 4, 2, 9, 0, 6, 16, 12, 0, 8, 25, 0, 0, 0, 20, 36, 18, 24, 0, 0, 12, 49, 0, 0, 0, 0, 0, 42, 64, 56, 0, 48, 0, 0, 0, 32, 81, 0, 72, 0, 0, 0, 0, 0, 54, 100, 50, 0, 0, 80, 0, 0, 0, 0, 40, 121, 0, 0, 0, 0, 0, 0, 0, 0, 0, 110, 144, 108, 96, 72, 0, 72, 0, 0, 0, 0, 0, 48

Offset

1,2

Links

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

Formula

T(n,1) = n^2.

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

Example

First few rows of the triangle are:
1;
4, 2;
9, 0, 6;
16, 12, 0, 8;
25, 0, 0, 0, 20;
36, 18, 24, 0, 0, 12;
49, 0, 0, 0, 0, 0, 42;
64, 56, 0, 48, 0, 0, 0, 32;
81, 0, 72, 0, 0, 0, 0, 0, 54;
...

Maple

A127470 := proc(n, k)
    add( A127466(n, j)*A051731(j, k), j=k..n) ;
end proc: # R. J. Mathar, Sep 08 2013

Crossrefs

Cf. A127466, A051731, A127469 (row sums), A061949.

Sequence in context: A190477 A143311 A016696 * A199449 A010649 A067721

Adjacent sequences: A127467 A127468 A127469 * A127471 A127472 A127473

Keyword

nonn,tabl

Author

Gary W. Adamson, Jan 15 2007

Extensions

Terms corrected by R. J. Mathar, Sep 08 2013

Status

approved