login

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 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A197042
Number of nX3 0..4 arrays with each element x equal to the number its horizontal and vertical neighbors equal to 4,2,0,1,3 for x=0,1,2,3,4
1
2, 20, 120, 698, 4080, 24074, 141856, 833758, 4909544, 28899922, 170120402, 1001361542, 5894102732, 34694985108, 204224876622, 1202124327402, 7076038423114, 41651567268298, 245173129915012, 1443158678807678
OFFSET
1,1
COMMENTS
Every 0 is next to 0 4's, every 1 is next to 1 2's, every 2 is next to 2 0's, every 3 is next to 3 1's, every 4 is next to 4 3's
Column 3 of A197047
LINKS
FORMULA
Empirical: a(n) = 3*a(n-1) +6*a(n-2) +39*a(n-3) +104*a(n-4) +320*a(n-5) -266*a(n-6) +209*a(n-7) -606*a(n-8) +472*a(n-9) -2199*a(n-10) -4220*a(n-11) -79*a(n-12) -4287*a(n-13) -1432*a(n-14) +665*a(n-15) -2303*a(n-16) -1803*a(n-17) +149*a(n-18) +1299*a(n-19) +3913*a(n-20) +1651*a(n-21) -2432*a(n-22) -901*a(n-23) +874*a(n-24) +148*a(n-25) -184*a(n-26) -32*a(n-27)
EXAMPLE
Some solutions for n=4
..1..2..0....1..0..2....0..2..0....0..0..0....0..0..2....1..0..1....2..0..0
..0..0..0....2..0..0....2..2..0....2..1..1....2..1..0....2..0..2....0..2..1
..2..2..1....0..1..2....0..0..2....0..0..2....0..1..0....0..1..0....0..2..1
..0..0..0....2..0..0....2..0..1....1..2..0....0..2..0....0..2..0....2..0..0
CROSSREFS
Sequence in context: A219759 A196797 A196585 * A350549 A377508 A062189
KEYWORD
nonn
AUTHOR
R. H. Hardin Oct 08 2011
STATUS
approved