A198669 - OEIS

%I #10 Feb 19 2025 16:16:18

%S 0,1,1,1,3,1,2,13,13,2,3,65,132,65,3,6,401,2715,2715,401,6,11,2798,

%T 59281,199923,59281,2798,11,23,21243,1544783,16089057,16089057,

%U 1544783,21243,23,47,170477,40546053,1382332582,4202762288,1382332582,40546053,170477

%N T(n,k) is the number of n X k 0..4 arrays with values 0..4 introduced in row major order and each element equal to one or two horizontal and vertical neighbors.

%H R. H. Hardin, <a href="/A198669/b198669.txt">Table of n, a(n) for n = 1..60</a>

%e Table starts:

%e ...0.......1..........1............2.............3.............6

%e ...1.......3.........13...........65...........401..........2798

%e ...1......13........132.........2715.........59281.......1544783

%e ...2......65.......2715.......199923......16089057....1382332582

%e ...3.....401......59281.....16089057....4202762288.1169280626549

%e ...6....2798....1544783...1382332582.1169280626549

%e ..11...21243...40546053.119026441960

%e ..23..170477.1100262051

%e ..47.1414186

%e .103

%e Some solutions with all values 0 to 4 for n=4 and k=3:

%e ..0..1..1....0..0..1....0..1..2....0..1..1....0..1..1....0..0..1....0..1..1

%e ..0..2..2....2..2..1....0..1..2....0..0..1....0..0..0....2..2..1....0..2..3

%e ..3..3..0....2..3..3....3..4..4....2..2..3....2..2..3....3..1..1....0..2..3

%e ..4..4..0....4..4..4....3..2..2....4..4..3....4..4..3....3..4..4....4..4..3

%K nonn,tabl,changed

%O 1,5

%A _R. H. Hardin_, Oct 28 2011