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A237855
Number of (n+1)X(4+1) 0..1 arrays with no element greater than all horizontal neighbors or less than all vertical neighbors
1
12, 114, 773, 4826, 31651, 213165, 1428967, 9520138, 63406826, 422805151, 2820139782, 18807174933, 125411082761, 836287781961, 5576801777184, 37189049253066, 247995097101165, 1653753070681134, 11028044588822481
OFFSET
1,1
COMMENTS
Column 4 of A237859
LINKS
FORMULA
Empirical: a(n) = 8*a(n-1) -20*a(n-2) +71*a(n-3) +6*a(n-4) +62*a(n-5) +230*a(n-6) +271*a(n-7) -483*a(n-8) -760*a(n-9) -1175*a(n-10) +355*a(n-11) +1437*a(n-12) +407*a(n-13) -1089*a(n-14) -275*a(n-15) +318*a(n-16) +82*a(n-17) -25*a(n-18) -17*a(n-19) -a(n-20) +a(n-21)
EXAMPLE
Some solutions for n=5
..1..1..1..1..1....0..1..1..1..1....1..1..1..1..1....0..1..1..0..0
..0..1..1..1..1....0..1..1..1..0....0..1..1..1..1....0..1..1..0..0
..0..0..0..0..0....0..1..1..1..0....0..1..1..1..1....0..1..1..0..0
..0..0..0..0..0....0..0..1..1..1....0..1..1..1..1....1..1..1..0..0
..0..0..1..1..0....0..0..0..1..1....1..1..0..1..1....0..1..1..1..0
..0..0..1..1..0....1..1..0..1..1....1..1..0..1..1....0..1..1..1..0
CROSSREFS
Sequence in context: A198375 A124651 A231379 * A055287 A080630 A005543
KEYWORD
nonn
AUTHOR
R. H. Hardin, Feb 14 2014
STATUS
approved