A144021 Eigentriangle by rows, T(n,k) = A000034(n-k+1)*A105476(k-1).

1, 2, 1, 1, 2, 3, 2, 1, 6, 6, 1, 2, 3, 12, 15, 2, 1, 6, 6, 30, 33, 1, 2, 3, 12, 15, 66, 78, 2, 1, 6, 6, 30, 33, 156, 177, 1, 2, 3, 12, 15, 66, 78, 354, 411, 2, 1, 6, 6, 30, 33, 156, 177, 822, 942

Offset

1,2

Comments

Row sums = A105476: (1, 3, 6, 15, 33, 78,...).

Left column = A000034: (1, 2, 1, 2, 1, 2,...).

Right border = A105476 shifted: (1, 1, 3, 6, 15, 33, 78,...).

Links

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

Formula

Eigentriangle by rows, A000034(n-k+1)*A105476(k-1); where A105476(k-1) = A105476 shifted = (1, 1, 3, 6, 15, 33, 78, 177,...).

Example

First few rows of the triangle =
1;
2, 1;
1, 2, 3
2, 1, 6, 6
1, 2, 3, 12, 15
2, 1, 6, 6, 30, 33;
1, 2, 3, 12, 15, 66, 78
2, 1, 6, 6, 30, 33, 156, 177;
1, 2, 3, 12, 15, 66, 78, 354, 411;
...
Row 4 = (2, 1, 6, 6) = termwise product of (2, 1, 2, 1) and (1, 1, 3, 6) = (2*1, 1*1, 2*3, 1*6).

Crossrefs

Cf. A000034, A105476.

Sequence in context: A143066 A338198 A091598 * A334591 A177962 A246552

Adjacent sequences: A144018 A144019 A144020 * A144022 A144023 A144024

Keyword

nonn

Author

Gary W. Adamson, Sep 07 2008

Status

approved