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

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A268766 T(n,k)=Number of nXk binary arrays with some element plus some horizontally, vertically, diagonally or antidiagonally adjacent neighbor totalling two exactly once. 7

%I

%S 0,1,1,2,6,2,5,15,15,5,10,44,56,44,10,20,105,223,223,105,20,38,258,

%T 762,1148,762,258,38,71,595,2607,5170,5170,2607,595,71,130,1368,8500,

%U 23156,32056,23156,8500,1368,130,235,3069,27411,99057,193573,193573,99057

%N T(n,k)=Number of nXk binary arrays with some element plus some horizontally, vertically, diagonally or antidiagonally adjacent neighbor totalling two exactly once.

%C Table starts

%C ...0....1......2.......5........10.........20...........38............71

%C ...1....6.....15......44.......105........258..........595..........1368

%C ...2...15.....56.....223.......762.......2607.........8500.........27411

%C ...5...44....223....1148......5170......23156........99057........418924

%C ..10..105....762....5170.....32056.....193573......1129042.......6475898

%C ..20..258...2607...23156....193573....1552272.....12111209......92571436

%C ..38..595...8500...99057...1129042...12111209....127676872....1312123185

%C ..71.1368..27411..418924...6475898...92571436...1312123185...18045771274

%C .130.3069..86622.1736105..36505596..696659613..13311824510..245588158242

%C .235.6830.270955.7122856.203462597.5178525870.133228716170.3292985469950

%H R. H. Hardin, <a href="/A268766/b268766.txt">Table of n, a(n) for n = 1..1404</a>

%F Empirical for column k:

%F k=1: a(n) = 2*a(n-1) +a(n-2) -2*a(n-3) -a(n-4)

%F k=2: a(n) = 2*a(n-1) +3*a(n-2) -4*a(n-3) -4*a(n-4)

%F k=3: a(n) = 4*a(n-1) +2*a(n-2) -16*a(n-3) -a(n-4) +12*a(n-5) -4*a(n-6)

%F k=4: [order 8]

%F k=5: [order 12]

%F k=6: [order 16]

%F k=7: [order 28]

%e Some solutions for n=4 k=4

%e ..0..1..0..1. .1..0..0..0. .1..0..0..1. .0..0..0..1. .0..1..1..0

%e ..0..1..0..0. .0..0..0..1. .0..0..0..0. .0..0..0..1. .0..0..0..0

%e ..0..0..0..1. .0..1..0..0. .0..0..1..0. .0..0..0..0. .0..0..0..1

%e ..0..1..0..0. .0..1..0..0. .0..1..0..0. .1..0..0..1. .0..1..0..0

%Y Column 1 is A001629.

%Y Column 2 is A193449.

%K nonn,tabl

%O 1,4

%A _R. H. Hardin_, Feb 13 2016

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.

Last modified March 25 13:23 EDT 2023. Contains 361524 sequences. (Running on oeis4.)