OFFSET
3,1
REFERENCES
A. J. Guttmann, Polygons, Polyominoes and Polycubes, Lecture Notes in Physics Volume 775, 2009, Chapter 16.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
LINKS
M. F. Sykes et al., Lattice constant systems and graph theory, J. Math. Phys., 7 (1966), 1557-1572.
MATHEMATICA
a[n_] := A001337[[n]]/(2n);
a /@ Range[3, 17] (* Jean-François Alcover, Jan 20 2020 *)
CROSSREFS
KEYWORD
nonn,more,nice
AUTHOR
EXTENSIONS
More terms from Ruperto Corso, Dec 19 2011
a(15) and a(16) from Sean A. Irvine, Mar 30 2017
a(17) from Bert Dobbelaere, Jan 14 2019
STATUS
approved