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A293917
Number of linear chord diagrams having n chords and minimal chord length four.
2
1, 19, 252, 3441, 52938, 919077, 17783732, 379205917, 8832657552, 223147872970, 6078406509776, 177602480890788, 5541376133638552, 183896037042429100, 6468180930063929404, 240368899912444102612, 9410883311417206598912, 387192534875365889313239
OFFSET
4,2
LINKS
FORMULA
a(n) ~ (exp(-3) - exp(-4)) * 2^(n + 1/2) * n^n / exp(n). - Vaclav Kotesovec, Oct 25 2017
CROSSREFS
Column k=4 of A293881.
Sequence in context: A018912 A021202 A125454 * A009762 A017952 A055433
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Oct 19 2017
STATUS
approved