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A168261 Triangle read by rows, A115361 * the diagonalized variant of A018819. 2
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 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,6

COMMENTS

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

= 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

Let 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.

Triangle A168261 = M*Q as infinite lower triangular matrices.

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: A152459 A275784 A097608 * A180997 A143439 A105469

Adjacent sequences:  A168258 A168259 A168260 * A168262 A168263 A168264

KEYWORD

nonn,tabl

AUTHOR

Gary W. Adamson, Nov 21 2009

STATUS

approved

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Last modified February 16 20:45 EST 2019. Contains 320189 sequences. (Running on oeis4.)