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A005500 Triangulations of the disk R_{n,1}.
(Formerly M1516)
19
1, 2, 5, 18, 88, 489, 3071, 20667, 146381, 1072760, 8071728, 61990477, 484182622 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

A row or column of the array in A169808.

Graphs can be enumerated and counted using the tool "plantri", in particular the command "./plantri -s -P4 -c2m2 [n]". - Manfred Scheucher, Mar 08 2018

REFERENCES

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.

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

LINKS

Table of n, a(n) for n=0..12.

G. Brinkmann and B. McKay, Plantri (program for generation of certain types of planar graph)

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)

C. F. Earl & N. J. A. Sloane, Correspondence, 1980-1981

FORMULA

a(n) = (A005505(n) + A002710(n))/2. - Max Alekseyev, Oct 29 2012

CROSSREFS

Cf. A002710, A005505, A169808.

Sequence in context: A142153 A287227 A094294 * A020025 A113715 A227094

Adjacent sequences:  A005497 A005498 A005499 * A005501 A005502 A005503

KEYWORD

nonn,more

AUTHOR

N. J. A. Sloane

EXTENSIONS

Edited by Max Alekseyev, Oct 29 2012

a(7)-a(12) from Manfred Scheucher, Mar 08 2018

STATUS

approved

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Last modified October 15 15:14 EDT 2019. Contains 328030 sequences. (Running on oeis4.)