The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.



(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A066158 Number of fixed polyominoes with n cells and tree-like structure. 11


%S 1,2,6,18,55,174,570,1908,6473,22202,76886,268352,942651,3329608,

%T 11817582,42120340,150682450,540832274,1946892842,7027047848,

%U 25424079339,92185846608,334925007128,1219054432490,4444545298879,16229462702152,59347661054364

%N Number of fixed polyominoes with n cells and tree-like structure.

%C Computed by a modified version of the program used for A065068.

%C Aleksandrowicz and Barequet (2011) confirm first 27 terms. [Gill Barequet, May 25 2011]

%D G. Aleksandrowicz and G. Barequet, Parallel enumeration of lattice animals, Proc. 5th Int. Frontiers of Algorithmics Workshop, Zhejiang, China, Lecture Notes in Computer Science, 6681, Springer-Verlag, 90-99, May 2011.

%D N. Madras, C. E. Soteros, S. G. Whittington, J. L. Martin, M. F. Sykes et al., The free energy of a collapsing branched polymer, J. Phys. A: Math. Gen. 23 (1990) 5327-5350.

%H I. Jensen, <a href="/A066158/b066158.txt">Table of n, a(n) for n = 1..44</a> [From the arXiv paper]

%H Gill Barequet, Gil Ben-Shachar, Martha Carolina Osegueda, <a href="http://www1.pub.informatik.uni-wuerzburg.de/eurocg2020/data/uploads/papers/eurocg20_paper_23.pdf">Applications of Concatenation Arguments to Polyominoes and Polycubes</a>, EuroCG '20, 36th European Workshop on Computational Geometry, (W├╝rzburg, Germany, 16-18 March 2020).

%H I. Jensen, <a href="https://doi.org/10.1023/A:1004855020556">Enumerations of lattice animals and trees</a>, J. Stat. Phys. 103 (3-4) (2001) 865-881, Table II.

%H I. Jensen, <a href="http://arxiv.org/abs/cond-mat/0007239">Enumerations of lattice animals and trees</a>, arXiv:cond-mat/0007239.

%Y Cf. A001168 (fixed polyominoes), A019441 (coefficients of g.f. related to this sequence), A118356, A191094, A191095, A191096, A191097, A191098 (fixed tree-like polycubes in 3, 4, 5, 6, 7, and 8 dimensions, resp.).

%K nonn

%O 1,2

%A _Jan Kristian Haugland_, Dec 13 2001

%E Added a(18) and a(19) from Madras et al. - _R. J. Mathar_, Apr 08 2006

%E Terms from a(20) on added by _N. J. A. Sloane_, Nov 05 2008, from the Jensen paper.

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified April 22 19:11 EDT 2021. Contains 343177 sequences. (Running on oeis4.)