

A006065


Maximal number of 4tree rows in ntree orchard problem.
(Formerly M0290)


7



0, 0, 0, 1, 1, 1, 2, 2, 3, 5, 6, 7, 9, 10, 12, 15, 16, 18, 20, 23
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

1,7


COMMENTS

Maximum number of rows with exactly 4 trees in each row if there are n trees in the orchard.
For further references and links see A003035.


REFERENCES

M. Gardner, Time Travel and Other Mathematical Bewilderments. Freeman, NY, 1988, Chap. 22.
F. Levi, Geometrische Konfigurationen, Hirzel, Leipzig, 1929.
Xianzu Lin, A new result about orchardplanting problem, Preprint, 2005. [Shows a(20) >= 23.]
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
For further references and links see A003035.


LINKS

P. Berloquin, a(12) >= 7 (from an article in Jeux & Strategies from 1983  see Fig. 10).
S. A. Burr, B. Grünbaum and N. J. A. Sloane, The Orchard Problem, Geometriae Dedicata, 2 (1974), 397424.
S. A. Burr, B. Grünbaum and N. J. A. Sloane, The Orchard Problem, Geometriae Dedicata, 2 (1974), 397424.
Branko Grünbaum and J. F. Rigby, The real configuration (21_4), Journal of the London Mathematical Society 2.2 (1990): 336346. [Shows a(21) >= 21.]
Ed Pegg, Jr., Mathpuzzxle Blog, Updated Feb 27 2020. [Gives new construction for n = 22]
Ed Pegg, Jr., Mathpuzzxle Blog, Updated Feb 27 2020. [Gives new construction for n = 22] (extract, local copy)


FORMULA



CROSSREFS

Cf. A172992 (the same problem, but with integervalued tree coordinates).


KEYWORD

nonn,hard,nice,more


AUTHOR



EXTENSIONS



STATUS

approved



