OFFSET
1,2
REFERENCES
Steven R. Finch, Mathematical Constants, Cambridge, 2003, pp. 342-349.
J. Katzenelson and R. P. Kurshan, S/R: A Language for Specifying Protocols and Other Coordinating Processes, pp. 286-292 in Proc. IEEE Conf. Comput. Comm., 1986.
LINKS
Sean A. Irvine, Table of n, a(n) for n = 1..18
Steven R. Finch, Hard Square Entropy Constant [Broken link]
Steven R. Finch, Hard Square Entropy Constant [From the Wayback machine]
Sean A. Irvine, Java program (github)
V. Kotesovec, Non-attacking chess pieces, 6ed, 2013, p. 73.
EXAMPLE
neighbors for n=4:
.|/ |/ |/ |/
-o--o--o--o-
/| /| /| /|
.|/ |/ |/ |/
-o--o--o--o-
/| /| /| /|
.|/ |/ |/ |/
-o--o--o--o-
/| /| /| /|
.|/ |/ |/ |/
-o--o--o--o-
/| /| /| /|
PROG
(S/R) proc a
stvar $[N][N]:boolean
init $[][] := false
cyset true
asgn $[][]->{false, true}
kill +[i in 0.. N-1](
+[j in 0.. N-1](
$[i][j]`*(
$[i][(j+1) mod N]`
+$[(i-1) mod N][(j+1) mod N]`
+$[(i-1) mod N][j]` ))) end
CROSSREFS
KEYWORD
nonn,hard
AUTHOR
R. H. Hardin, Jan 25 2002
EXTENSIONS
Terms a(11)-a(12) from Vaclav Kotesovec, May 07 2012
a(13) from Vaclav Kotesovec, Aug 15 2016
a(14) from Vaclav Kotesovec, May 24 2021
a(15)-a(16) from Sean A. Irvine, Nov 18 2023
STATUS
approved