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A129047
Number of n-node triangulations of the Klein bottle N_2 in which every node has degree >= 4.
0
0, 6, 133, 1971, 23541, 245261, 2326207, 20685641, 175544819, 1438903377, 11485167375
OFFSET
7,2
REFERENCES
G. Ringel, Wie man die geschlossenen nichtorientierbaren Flaechen in moeglichst wenig Dreiecke zerlegen kann, Math. Ann. 130 (1955), 317-326.
CROSSREFS
Sequence in context: A350611 A247012 A003373 * A209276 A244745 A179564
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, May 13 2007
STATUS
approved