login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A220550 Number of ways to reciprocally link elements of an nX5 array either to themselves or to exactly one horizontal, vertical or antidiagonal neighbor 1
8, 401, 14556, 565061, 21668208, 832899775, 32001129185, 1229633337183, 47247493674864, 1815445803499208, 69756959373004005, 2680352078247056300, 102990256079543046348, 3957313286001327139326, 152056408321267850998276 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 5 of A220553

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..210

FORMULA

Empirical: a(n) = 21*a(n-1) +607*a(n-2) +2818*a(n-3) -13422*a(n-4) -102307*a(n-5) +102787*a(n-6) +1377367*a(n-7) -625026*a(n-8) -9368158*a(n-9) +6655110*a(n-10) +30101928*a(n-11) -31218870*a(n-12) -45617582*a(n-13) +65294634*a(n-14) +29766481*a(n-15) -68435485*a(n-16) -4100689*a(n-17) +40652394*a(n-18) -5180290*a(n-19) -14692966*a(n-20) +3231432*a(n-21) +3351718*a(n-22) -849954*a(n-23) -490034*a(n-24) +118041*a(n-25) +45619*a(n-26) -8829*a(n-27) -2574*a(n-28) +334*a(n-29) +79*a(n-30) -5*a(n-31) -a(n-32)

EXAMPLE

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

..0..7..0..0..7....0..6..4..8..8....8..6..4..0..0....8..0..8..0..7

..3..6..4..3..7....0..0..8..2..2....2..7..8..0..7....2..0..2..3..0

..6..4..0..3..0....6..4..2..6..4....3..0..2..3..0....0..0..0..6..4

CROSSREFS

Sequence in context: A347997 A221224 A281439 * A191874 A323575 A183579

Adjacent sequences:  A220547 A220548 A220549 * A220551 A220552 A220553

KEYWORD

nonn

AUTHOR

R. H. Hardin Dec 15 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 | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified August 16 05:55 EDT 2022. Contains 356160 sequences. (Running on oeis4.)