A133200 A001263 * A136521 as infinite lower triangular matrices, where A001263 = the Narayana triangle and A136521 = an infinite lower triangular matrix with (1, 2, 2, 2, ...) in the main diagonal and the rest zeros.

1, 1, 2, 1, 6, 2, 1, 12, 12, 2, 1, 20, 40, 20, 2, 1, 30, 100, 100, 30, 2, 1, 42, 210, 350, 210, 42, 2, 1, 56, 392, 980, 980, 392, 56, 2, 1, 72, 672, 2352, 3528, 2352, 672, 72, 2, 1, 90, 1080, 5040, 10584, 10584, 5040, 1080, 90, 2

Offset

1,3

Comments

Row sums = A131428 starting (1, 3, 9, 27, 83, 263, ...).

Links

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

Example

First few rows of the triangle:
  1;
  1,  2;
  1,  6,   2;
  1, 12,  12,   2;
  1, 20,  40,  20,   2;
  1, 30, 100, 100,  30,  2;
  1, 42, 210, 350, 210, 42, 2;
  ...

Crossrefs

Cf. A001263, A136521.

Sequence in context: A208905 A208749 A208751 * A103881 A101024 A124730

Adjacent sequences: A133197 A133198 A133199 * A133201 A133202 A133203

Keyword

nonn,tabl

Author

Gary W. Adamson, Jan 02 2008

Status

approved