A168261 Triangle read by rows, A115361 * the diagonalized variant of A018819.

1, 1, 1, 0, 0, 2, 1, 1, 0, 2, 0, 0, 0, 0, 4, 0, 0, 2, 0, 0, 4, 0, 0, 0, 0, 0, 0, 6, 1, 1, 0, 2, 0, 0, 0, 6, 0, 0, 0, 0, 0, 0, 0, 0, 10, 0, 0, 0, 0, 4, 0, 0, 0, 0, 10, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 14, 0, 0, 2, 0, 0, 4, 0, 0, 0, 0, 0, 14, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 20

Offset

1,6

Comments

Row sums = A018819 starting with offset 1; (1, 2, 2, 4, 4, 6, 6, 10, 10,...).

Equals the eigensequence of triangle A115361.

Rightmost diagonal = A018819.

Sum of n-th row terms = rightmost term of next row.

Links

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

Formula

Equals M*Q as infinite lower triangular matrices, where M = triangle A115361, and Q = the diagonalized variant of A018819 such that (1, 1, 2, 2, 4, 4, 6, 6,...) = rightmost diagonal with the rest zeros.

Example

First few rows of the triangle =
1;
1, 1;
0, 0, 2;
1, 1, 0, 2;
0, 0, 0, 0, 4;
0, 0, 2, 0, 0, 4;
0, 0, 0, 0, 0 0, 6;
1, 1, 0, 2, 0, 0, 0, 6;
0, 0, 0, 0, 0, 0, 0, 0, 10;
0, 0, 0, 0, 4, 0, 0, 0, 0, 10;
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 14;
0, 0, 2, 0, 0, 4, 0, 0, 0, 0, 0, 14;
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 20;
0, 0, 0, 0, 0, 0, 6, 0, 0, 0, 0, 0, 0, 20;
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 26;
1, 1, 0, 2, 0, 0, 0, 6, 0, 0, 0, 0, 0, 0, 0, 26;
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 36;
...

Crossrefs

Cf. A115361, A018819.

Sequence in context: A097608 A331126 A362899 * A180997 A143439 A105469

Adjacent sequences: A168258 A168259 A168260 * A168262 A168263 A168264

Keyword

nonn,tabl

Author

Gary W. Adamson, Nov 21 2009

Status

approved