A143311 Triangle read by rows, A127648 * A126988; 1<=k<=n.

1, 4, 2, 9, 0, 3, 16, 8, 0, 4, 25, 0, 0, 0, 5, 36, 18, 12, 0, 0, 6, 49, 0, 0, 0, 0, 0, 7, 64, 32, 0, 16, 0, 0, 0, 8, 81, 0, 27, 0, 0, 0, 0, 0, 9, 100, 50, 0, 0, 20, 0, 0, 0, 0, 10, 121, 0, 0, 0, 0, 0, 0, 0, 0, 0, 11, 144, 72, 48, 36, 0, 24, 0, 0, 0, 0, 0, 12, 169, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 13

Offset

1,2

Comments

Row sums = A064987, n*sigma(n): (1, 6, 12, 28, 30, 72, 56,...).

Links

Table of n, a(n) for n=1..91.

Formula

Triangle read by rows, A127648 * A126988; 1<=k<=n

Example

First few rows of the triangle =
1;
4, 2;
9, 0, 3;
16, 8, 0, 4;
25, 0, 0, 0, 5;
36, 18, 12, 0, 0, 6;
49, 0, 0, 0, 0, 0, 7;
64, 32, 0, 16, 0, 0, 0, 8;
...

Crossrefs

Cf. A127648, A126988, A064987.

Sequence in context: A046589 A072562 A190477 * A016696 A127470 A199449

Adjacent sequences: A143308 A143309 A143310 * A143312 A143313 A143314

Keyword

nonn,tabl

Author

Gary W. Adamson, Aug 06 2008

Status

approved