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

 

Logo

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 56th year, we are closing in on 350,000 sequences, and we’ve crossed 9,700 citations (which often say “discovered thanks to the OEIS”).

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A220651 Number of ways to reciprocally link elements of an nX6 array either to themselves or to exactly two king-move neighbors, without 3-loops 1
1, 1441, 816159, 389859889, 179768901595, 85240331175084, 40274546959211319, 19024400007896312662, 8986807181301920000278, 4245342275704299946914591, 2005473806376394839453915403, 947373651435473076102298469864 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Column 6 of A220652

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..38

EXAMPLE

Some solutions for n=3 0=self 1=nw 2=n 3=ne 4=w 6=e 7=sw 8=s 9=se (reciprocal directions total 10)

.00.67.46.48.69.47...00.00.00.78.68.48...00.69.46.49.69.47...00.00.78.00.79.00

.36.48.00.28.39.17...00.00.39.27.28.28...00.79.16.48.13.17...00.38.26.34.00.17

.00.26.46.24.36.14...00.00.36.14.26.24...36.46.14.26.34.00...00.26.46.46.34.00

CROSSREFS

Sequence in context: A119422 A166609 A178275 * A252224 A221872 A251842

Adjacent sequences:  A220648 A220649 A220650 * A220652 A220653 A220654

KEYWORD

nonn

AUTHOR

R. H. Hardin Dec 17 2012

STATUS

approved

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 December 3 11:58 EST 2021. Contains 349462 sequences. (Running on oeis4.)