A293916 Number of linear chord diagrams having n chords and minimal chord length three.

1, 9, 79, 854, 11105, 167273, 2855096, 54426601, 1146050151, 26418261876, 661704149855, 17894827830455, 519672858520861, 16129429179859894, 532839970205194270, 18667063990244959414, 691265187531408182336, 26979801565685043088417, 1106929654165005908000185

Offset

3,2

Links

Alois P. Heinz, Table of n, a(n) for n = 3..404

Formula

a(n) ~ (exp(-2) - exp(-3)) * 2^(n + 1/2) * n^n / exp(n). - Vaclav Kotesovec, Oct 25 2017

Crossrefs

Column k=3 of A293881.

Sequence in context: A348895 A293723 A255807 * A293731 A254833 A342933

Adjacent sequences: A293913 A293914 A293915 * A293917 A293918 A293919

Keyword

nonn

Author

Alois P. Heinz, Oct 19 2017

Status

approved