A293920 Number of linear chord diagrams having n chords and minimal chord length seven.

1, 159, 7564, 245964, 6996588, 193799140, 5489211751, 162272284974, 5047554996855, 165595774518042, 5728636935767404, 208700950019470460, 7993330299623656154, 321268248361695869991, 13525506763517368392668, 595415097485805608016210, 27361311228606445955339071

Offset

7,2

Links

Alois P. Heinz, Table of n, a(n) for n = 7..405

Formula

a(n) ~ (exp(-6) - exp(-7)) * 2^(n + 1/2) * n^n / exp(n). - Vaclav Kotesovec, Oct 25 2017

Crossrefs

Column k=7 of A293881.

Sequence in context: A232408 A121800 A121804 * A281336 A205164 A221011

Adjacent sequences: A293917 A293918 A293919 * A293921 A293922 A293923

Keyword

nonn

Author

Alois P. Heinz, Oct 19 2017

Status

approved