A293998 Number of linear chord diagrams having n chords and no chord length larger than six.

1, 1, 3, 15, 105, 945, 10395, 45045, 222951, 1245257, 7689707, 50548041, 328681355, 1898148921, 10938090235, 64447508901, 388656309623, 2372510073525, 14406809496311, 86092382481933, 512757617989667, 3064484085534721, 18400499270245971, 110741448251269561

Offset

0,3

Links

Alois P. Heinz, Table of n, a(n) for n = 0..1000

Index entries for linear recurrences with constant coefficients, signature (3, 7, 7, 84, 939, 6095, -4433, -31187, -37164, -140858, -899154, -569580, 741066, 3256828, -1225088, 19146692, -26901488, 28568896, 21503648, -89813600, 175998288, -128442288, 44156064, -18953856, 34648704, 69766272, -7008768, 5868288, -82363392, -80815104, -46448640, -9953280)

Crossrefs

Column k=6 of A293960.

Sequence in context: A293997 A328866 A247304 * A293999 A294000 A294001

Adjacent sequences: A293995 A293996 A293997 * A293999 A294000 A294001

Keyword

nonn,easy

Author

Alois P. Heinz, Oct 21 2017

Status

approved