OFFSET
1,4
LINKS
Hans-J. Bandelt and Jarmila Hedlíková, Median algebras, Discrete Mathematics, 45 (1983), 1-30.
FORMULA
A001206(n) = Sum_{k=1..n} binomial(n,k)*a(k).
CROSSREFS
KEYWORD
hard,nonn,more
AUTHOR
Don Knuth, Jun 11 2005
EXTENSIONS
a(7)-a(8) from Vladeta Jovovic, Jun 13 2005
a(9) (using formula) from Pontus von Brömssen, Dec 29 2023
STATUS
approved