A067967 - OEIS

A067967

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

1, 5, 19, 217, 4076, 164258, 12285477, 1834600977, 527717587843, 296979228487760, 324881629286870822, 692625866382651263578, 2874716493700380888930840, 23237986479606982160703729647, 365788614113216462103977935612524, 11213018647250714014261414954480048385

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OFFSET

1,2

REFERENCES

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

LINKS

Table of n, a(n) for n=1..16.

Steven R. Finch, Hard Square Entropy Constant [Broken link]

Steven R. Finch, Hard Square Entropy Constant [From the Wayback machine]

EXAMPLE

Neighbors for n=4:

:\|/ | \|/ |

:-o--o--o--o-

: | /|\ | /|\

:\|/ | \|/ |

:-o--o--o--o-

: | /|\ | /|\

:\|/ | \|/ |

:-o--o--o--o-

: | /|\ | /|\

:\|/ | \|/ |

:-o--o--o--o-

: | /|\ | /|\

Neighbors for n=5:

:\|/ | \|/ | \|

:-o--o--o--o--o-

: | /|\ | /|\ |\

:\|/ | \|/ | \|

:-o--o--o--o--o-

: | /|\ | /|\ |\

:\|/ | \|/ | \|

:-o--o--o--o--o-

: | /|\ | /|\ |\

:\|/ | \|/ | \|

:-o--o--o--o--o-

: | /|\ | /|\ |\

:\|/ | \|/ | \|

:-o--o--o--o--o-

: | /|\ | /|\ |\

CROSSREFS

For bent instead of shifted for odd n see A066865.

Sequence in context: A058765 A317340 A328716 * A362281 A092751 A357363

Adjacent sequences: A067964 A067965 A067966 * A067968 A067969 A067970

KEYWORD

nonn

AUTHOR

R. H. Hardin, Feb 02 2002

EXTENSIONS

More terms from Sean A. Irvine, Nov 18 2023

STATUS

approved