1,2

Non-zero terms in every column = d(n), A000005: (1, 2, 2, 3, 2, 4, 2, 4,...). Row sums = A007425: (1, 3, 3, 6, 3, 9, 3, 10,...). A127170 * [1, 0, 0, 0,...] = A000005: (1, 2, 2, 3, 2, 4,...) A127170 * [1, 2, 3,...] = A007429: (1, 4, 10, 4, 16,...).

Contribution from Gary W. Adamson (qntmpkt(AT)yahoo.com), Apr 27 2009: (Start)

Eigensequence of the triangle = A007557. (i.e, sequence A007557 shifts to the

left upon multiplication by A127170.) (End)

Square of A051731 A000005, d(n); in every column k, interspersed with (k-1) zeros.

First few rows of the triangle are:

1;

2, 1;

2, 0, 1;

3, 2, 0, 1;

2, 0, 0, 0, 1;

4, 2, 2, 0, 0, 1;

2, 0, 0, 0, 0, 0, 1;

4, 3, 0, 2, 0, 0, 0, 1;

3, 0, 2, 0, 0, 0, 0, 0, 1;

4, 2, 0, 0, 2, 0, 0, 0, 0, 1;

...

Cf. A051731, A000005, A007425, A126988, A007429, A127170.

A007557 [From Gary W. Adamson (qntmpkt(AT)yahoo.com), Apr 27 2009]

Sequence in context: A144515 A028933 A143352 this_sequence A143335 A143365 A099505

Adjacent sequences: A127167 A127168 A127169 this_sequence A127171 A127172 A127173

nonn,tabl

Gary W. Adamson (qntmpkt(AT)yahoo.com), Jan 06 2007