OFFSET
1,2
COMMENTS
Related to the enumeration of rooted simple planar maps with n edges.
See A329776 for another version. Presumably only one of the two versions is correct.
REFERENCES
Liu, Yanpei, On the enumeration of simple planar maps, RUTCOR Research Report #37-87, Nov. 1987, RUTCOR, Hill Center, Rutgers University, NJ. See (20).
Liu, Yanpei, An enumerating equation of simple planar maps with face partition, RUTCOR Research Report #38-87, Nov. 1987, RUTCOR, Hill Center, Rutgers University, NJ. See (22).
LINKS
Yanpei Liu, On functional equations arising from map enumerations, Discrete Mathematics 123.1-3 (1993): 93-109. See (4.16).
MAPLE
f2:=n -> (1/n!)*add(4*(2*n+1)!*(2*n-i-4)!/(i!*(n-i-2)!*(2*n-i+1)), i=0..floor(n/2));
[1, 2, seq(f2(m), m=3..10)];
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Nov 25 2019
STATUS
approved