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 A066865 Number of binary arrangements without adjacent 1's on n X n staggered hexagonal torus bent for odd n. 4

%I

%S 1,5,22,217,4726,164258,14840533,1834600977,669877863205,

%T 296979228487760,434542100979981567

%N Number of binary arrangements without adjacent 1's on n X n staggered hexagonal torus bent for odd n.

%D Steven R. Finch, Mathematical Constants, Cambridge, 2003, pp. 342-349.

%D 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.

%H Steven R. Finch, <a href="http://www.people.fas.harvard.edu/~sfinch/constant/square/square.html">Hard Square Entropy Constant</a> [Broken link]

%H Steven R. Finch, <a href="http://web.archive.org/web/20010605012506/http://www.mathsoft.com/asolve/constant/square/square.html">Hard Square Entropy Constant</a> [From the Wayback machine]

%e Neighbors for n=4: (The dots here represent spaces)

%e \|/ | \|/ |

%e -o--o--o--o-

%e .| /|\ | /|\

%e \|/ | \|/ |

%e -o--o--o--o-

%e .| /|\ | /|\

%e \|/ | \|/ |

%e -o--o--o--o-

%e .| /|\ | /|\

%e \|/ | \|/ |

%e -o--o--o--o-

%e .| /|\ | /|\

%e Neighbors for n=5:

%e \|/ | \|/ | \|/

%e .o--o--o--o--o

%e /| /|\ | /|\ |\

%e \|/ | \|/ | \|/

%e .o--o--o--o--o

%e /| /|\ | /|\ |\

%e \|/ | \|/ | \|/

%e .o--o--o--o--o

%e /| /|\ | /|\ |\

%e \|/ | \|/ | \|/

%e .o--o--o--o--o

%e /| /|\ | /|\ |\

%e \|/ | \|/ | \|/

%e .o--o--o--o--o

%e /| /|\ | /|\ |\

%o [S/R] proc a

%o stvar \$[N][N]:boolean

%o init \$[][] := false

%o cyset true

%o asgn \$[][]->{false,true}

%o kill +[i in 0.. N-1](

%o +[j in 0.. N-1](

%o \$[i][j]`*(

%o (

%o \$[i][(j-1) mod N]`

%o +\$[(i-1) mod N][j]`

%o +(

%o \$[(i-1) mod N][(j-1) mod N]`

%o ? ((j mod 2)=0) |

%o \$[(i+1) mod N][(j-1) mod N]`

%o )

%o ) ? ((j>0)+((N mod 2)=0)) | (

%o \$[(i-1) mod N][j]`

%o +\$[(i-1) mod N][(j-1) mod N]`

%o +\$[(i+1) mod N][(j-1) mod N]` )))) end

%Y Cf. A006506 A027683 A066863 A066864 A066866, shifted instead of bent A067967.

%Y Row sums of A067015.

%K nonn

%O 1,2

%A _R. H. Hardin_, Jan 25, 2002

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Last modified June 5 16:19 EDT 2020. Contains 334852 sequences. (Running on oeis4.)