A291085 Irregular triangle read by rows: T(n,m) = number of lattice paths of type B^H terminating at point (n, m).

1, 1, 4, 4, 2, 1, 20, 19, 13, 8, 3, 1, 104, 98, 76, 52, 28, 13, 4, 1, 556, 526, 434, 319, 201, 111, 50, 19, 5, 1, 3032, 2887, 2470, 1910, 1316, 811, 436, 205, 80, 26, 6, 1, 16778, 16073, 14085, 11304, 8259, 5489, 3284, 1763, 833, 344, 119, 34, 7, 1, 93872, 90386, 80584, 66514, 50680, 35588, 22912, 13476, 7176, 3437, 1456, 539, 168, 43, 8, 1

Offset

0,3

Links

Table of n, a(n) for n=0..71.

Veronika Irvine, Lace Tessellations: A mathematical model for bobbin lace and an exhaustive combinatorial search for patterns, PhD Dissertation, University of Victoria, 2016.

Example

Triangle begins:
1,1,
4,4,2,1,
20,19,13,8,3,1,
104,98,76,52,28,13,4,1,
556,526,434,319,201,111,50,19,5,1,
3032,2887,2470,1910,1316,811,436,205,80,26,6,1,
16778,16073,14085,11304,8259,5489,3284,1763,833,344,119,34,7,1,
93872,90386,80584,66514,50680,35588,22912,13476,7176,3437,1456,539,168,43,8,1,
...

Crossrefs

First column is A291089.

Sequence in context: A168455 A300153 A182781 * A193556 A120438 A366470

Adjacent sequences: A291082 A291083 A291084 * A291086 A291087 A291088

Keyword

nonn,tabf

Author

N. J. A. Sloane, Aug 19 2017

Status

approved