A143594 Triangle read by rows, A051731 * (an infinite lower triangular matrix with 1's in the first column and the rest 2's).

1, 2, 2, 2, 2, 2, 3, 4, 2, 2, 2, 2, 2, 2, 2, 4, 6, 4, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 4, 6, 4, 4, 2, 2, 2, 2, 3, 4, 4, 2, 2, 2, 2, 2, 2, 4, 6, 4, 4, 4, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 6, 10, 8, 6, 4, 4, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2

Offset

1,2

Comments

Left column = d(n), A000005: (1, 2, 2, 3, 2, 4, 2,...).

Prime rows have all 2's.

Row sums = A129235: (1, 4, 6, 11, 10, 10,...).

Links

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

Formula

Triangle read by rows, A051731 * (an infinite lower triangular matrix with 1's in the first column and the rest 2's), i.e. (1; 1,2; 1,2,2;...), 1<=k<=n A051731 = the inverse Mobius transform.

Example

First few rows of the triangle =
1;
2, 2;
2, 2, 2;
3, 4, 2, 2;
2, 2, 2, 2, 2;
4, 6, 4, 2, 2, 2;
2, 2, 2, 2, 2, 2, 2;
...

Crossrefs

Cf. A129235, A000005, A051731.

Sequence in context: A242763 A018119 A177001 * A298949 A329097 A197054

Adjacent sequences: A143591 A143592 A143593 * A143595 A143596 A143597

Keyword

nonn,tabl

Author

Gary W. Adamson, Aug 26 2008

Status

approved