OFFSET
0,5
LINKS
Andrew Howroyd, Table of n, a(n) for n = 0..30
Antonio Breda d'Azevedo, Alexander Mednykh, and Roman Nedela, Enumeration of maps regardless of genus: Geometric approach, Discrete Mathematics, Volume 310, 2010, Pages 1184-1203.
FORMULA
a(n) = (A170946(n) - A170947(n)) / 2. [Breda d'Azevedo, Mednykh & Nedela, Corollary 4.8] - Andrey Zabolotskiy, Jun 06 2024
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Feb 21 2010
EXTENSIONS
Name clarified, a(0)=0 prepended and a(19) onwards added by Andrew Howroyd, Jan 27 2025
STATUS
approved