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A002713 Number of unrooted triangulations of the disk with n interior nodes and 3 nodes on the boundary.
(Formerly M3524 N1431)
4
1, 1, 1, 4, 16, 78, 457, 2938, 20118, 144113, 1065328, 8068332, 62297808, 488755938, 3886672165, 31269417102, 254141551498, 2084129777764, 17228043363781, 143432427097935, 1201853492038096, 10129428318995227, 85826173629557200 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,4
COMMENTS
These are also called [n,0]-triangulations.
REFERENCES
N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
LINKS
W. G. Brown, Enumeration of triangulations of the disk, Proc. London Math. Soc., 14 (1964), 746-768.
W. G. Brown, Enumeration of Triangulations of the Disk, Proc. Lond. Math. Soc. s3-14 (1964) 746-768. [Annotated scanned copy]
CombOS - Combinatorial Object Server, generate planar graphs
C. F. Earl and L. J. March, Architectural applications of graph theory, pp. 327-355 of R. J. Wilson and L. W. Beineke, editors, Applications of Graph Theory. Academic Press, NY, 1979. (Annotated scanned copy)
FORMULA
a(n) = (A002709(n) + A002712(n)) / 2.
CROSSREFS
Column k=0 of A169808.
Sequence in context: A138294 A014514 A000780 * A221763 A362750 A356406
KEYWORD
nonn
AUTHOR
EXTENSIONS
Terms a(9) onward from Max Alekseyev, May 11 2010
Name clarified by Andrew Howroyd, Feb 24 2021
STATUS
approved

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Last modified April 23 07:16 EDT 2024. Contains 371905 sequences. (Running on oeis4.)