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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A204712 Number of (n+1)X8 0..1 arrays with the permanents of all 2X2 subblocks equal and nonzero 1
385, 3473, 28161, 239425, 1992321, 16748161, 140090241, 1174759297, 9838208513, 82449830017, 690711971457, 5787565930753, 48489078457729, 406275347589249, 3403932556101121, 28520064001053825, 238954333647573121 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 7 of A204713

LINKS

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

Robert Israel, Maple-assisted proof of formula

FORMULA

Empirical: a(n) = 8*a(n-1) +50*a(n-2) -389*a(n-3) -790*a(n-4) +6534*a(n-5) +3836*a(n-6) -45232*a(n-7) +9360*a(n-8) +108928*a(n-9) -82304*a(n-10).

Empirical formula confirmed by Robert Israel, Jun 19 2018: see link.

EXAMPLE

Some solutions for n=4

..0..1..1..1..1..1..1..1....1..1..0..1..0..1..0..1....0..1..0..1..1..0..1..0

..1..0..1..0..1..0..1..0....0..1..1..1..1..0..1..1....1..0..1..0..1..1..1..1

..1..1..0..1..0..1..1..1....1..1..0..1..0..1..1..0....0..1..0..1..0..1..0..1

..0..1..1..0..1..0..1..0....0..1..1..0..1..0..1..1....1..1..1..1..1..1..1..0

..1..1..0..1..0..1..0..1....1..1..0..1..0..1..0..1....0..1..0..1..0..1..0..1

MAPLE

Configs:=  [seq(convert(2^8+i, base, 2)[1..8], i=0..2^8-1)]:

Compatible:= proc(i, j)

if andmap(k -> Configs[i][k]*Configs[j][k+1]+Configs[i][k+1]*Configs[j][k] = 1, [$1..7]) then 1 else 0 fi

end proc:

T:= Matrix(256, 256, Compatible):

u:= Vector[row](256, 1):

v:= Vector(256, 1):

TV[0]:= v:

for n from 1 to 30 do TV[n]:= T . TV[n-1] od:

seq(1+ u . TV[n], n=1..30); # Robert Israel, Jun 19 2018

CROSSREFS

Sequence in context: A065110 A200525 A225711 * A237102 A264421 A063390

Adjacent sequences:  A204709 A204710 A204711 * A204713 A204714 A204715

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 18 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 October 27 09:27 EDT 2021. Contains 348272 sequences. (Running on oeis4.)